D&D 5.5e Rules — Hiding and Cover and Surprise and Initiative

Some clearer rules on this would be great. Alas, things are fuzzier than ideal.

This post is just focusing on D&D 5.5e (2024) rules. This general category is so messy, I don’t dare try to simultaneously describe the 5e (2014) variants.

Some of this material is already covered (so to speak) in my posts on Cover and Surprise. At some point in time I should probably integrate it together, but, until then …

Surprise

5.5e significantly changed the Surprise rules. Gone is the “you’re frozen until your first turn, then you’re still gimped until your next turn” stuff, in exchange for being at Disadvantage on Initiative. 5.5e also tried to normalize the Hiding / Cover aspects of Surprise, in part by making being Hidden the functional equivalent (and called it by the name) of being Invisible (i.e., having the Invisible condition). Which sometimes makes for odd situations, but …

After a session where things got a bit complicated, I did a re-read of the 5.5e rules (links for all this are down below). The rules, as always, look straightforward, a framework that should make sense, whether it does or not. The devil, as always, is in applying it to an actual combat situation.

I’ve linked to some of the rules at the bottom of the post, and [footnoted] to them in what I’ve collected below.

At any rate, fundamentally Surprise happens under a combination of two conditions:

when a combatant is “caught unawares by the start of combat” [3] or, as phrased in the 5e rules, “doesn’t notice a threat.”
in a case where being covert (in movement / positioning (Stealth), or in behavior (Deception)) is better than a target’s awareness (spotting someone (Perception), or being aware of their motivation (Insight); this is likely a Passive check, since you only Actively try to perceive such things when you are already aware of the risk/threat of the situation, and so aren’t prone to Surprise because of the first condition).

That second condition is mechanical — dueling skills of various sorts. The first is a bit more subjective and narrative, and requires some adjudication. Can a guard who is watching for an attack be caught unawares? If you’re creeping down a dungeon corridor, looking for an ambush, are you aware that there is a threat (even if you don’t know it specifically)? How long can you be actively alert for such stuff (that guard might be flagging by the end of the third watch)? What if the type of combat or threat is itself unexpected (the goblins drop down through the illusory ceiling)?

That’s all why they pay DMs the big bucks.

Something that may tie into both of these aspects is Travel Pace[7]. This often comes up in overland travel from Point A to Point B, but can be applicable within a dungeon — and both affects some of the rolls above as well as the attitude: e.g., if the players say they are walking at a fast pace to get to the dungeon ahead, there are mechanical effect on their senses, but it’s also an implication they aren’t expecting an attack.

Walking Pace	Feet/min	MPH	Miles / day	Notes
Fast	400	4	30	DISadvantage on Percept, Survival, Stealth
Normal	300	3	24	DISadvantage on Stealth
Slow	200	2	18	ADVantage on Percept, Survival

Surprise is also individual — the Surprise status of each creature on one side or the other can vary depending on the above factors.

Our focus here is mostly on the Surprise that comes from an Attacker being physically Hidden, but bear in mind that it can be broader than that is useful.

Hiding = Invisibility

A potential Attacker can use the Hide action, making DC 15 Stealth check while out of the Opponent’s line of sight, and while[2] …

Heavily Obscured
behind Three-Quarter Cover
behind Total Cover

… to effectively become Invisible.[2] (The D20 check rolled by the person Hiding is the DC for someone to Perceive them[2]).

This can be for teeing up an ambush, or mid-battle sneaking about. To get all the advantages of being Hidden, though, you have to have explicitly taken the Hide action; otherwise you’re just getting protection from cover.

Rolling Initiative

First off, Initiative is rolled when combat starts.[4] Not after someone gets in the first blow or their sneaky alpha strike from cover, but when attack dice are about to be rolled.

If an Attacker is initiating the combat (“Okay, team, I’m going to be in front and cast Fireball!”), the Attacker gets (DM’s discretion) Advantage on their Initiative roll.[6] (This one is hidden in the DMG as an option, and is the sop to the “But nobody is supposed to move until I cast my spell” issue.) This rule holds regardless of being Hidden or Surprised or not (yes, the guy who throws the first punch in the bar brawl rolls Initiative on Advantage to do it), but often comes up in context of an ambush or bursting into the enemy’s room.
If an Attacker is Invisible (Hidden and unknown to be there by the target), the Attacker gets Advantage on their Initiative roll.[1]
If the Opponents are Surprised (they didn’t know the Attacker was there and weren’t in “expecting combat” mode), they roll Initiative with Disadvantage.[3,4]

So let’s say Bob wants to get the drop on an Orc heading off to sleep. He positions himself around a corner (in Total Cover), and explicitly Hides himself (makes sure nothing is showing, tries to stay quiet, etc.). The Orc figures the hallways is safe and isn’t expecting any surprises, and their Passive Perception isn’t enough to meet the Stealth roll Bob made when he Hid.

Bob gets Advantage on Initiative for starting things, and would also get Advantage on Initiative because he is (until he attacks) Invisible. Advantage only adds once, of course.

The Orc doesn’t know Bob is there, and has no reason to be worried, so they get Disadvantage on Initiative. If the Orc knew that Bob had run away in this direction, and were watching out for him, they would roll Initiative normally. Ditto if they heard a noise from ahead and advanced cautiously.

Results of Initiative

If, after Initiative is rolled, there are allies who go before the Attacker initiating combat, then if they want the Attacker to get that first strike off, they need to Dodge or Help (if that applies) or, more likely, Ready an action. (This seems counter-intuitive, as it seems to penalize quick-reflexes folks; a Readied action isn’t as robust or useful as one normally taken. But that’s how it goes; the alternative is to blow the plan for that initiating Attacker to actually initiate the attack.)

If, after Initiative is rolled, any of the Opponents (even Surprised ones) still get a better Initiative than the hidden Attacker, they are (on the honor system) aware something is about to happen and can, within limits, respond first. Effectively, they are reacting to the Attacker popping out of hiding, even if they can’t directly do anything about it this turn. Faster Opponents can Dodge, try to Perceive the hidden attackers, warn their fellows, throw up magical defenses, etc.

In other words, those Opponents are still reacting faster than the Attacker, even if they can’t see them or directly attack them (yet).

The faster Opponents could, theoretically, Ready an action to shoot anyone who shows up “where I heard that noise.” If the Attacker is effectively Hidden / “Invisible,” that Readied action would not go off until after the Attacker did their thing, because that attack (see below) is what technically drops the “Invisibility” they have.[2]

Okay, so that handles Initiative … how about actual attacks (and counter-attacks)?

Attacks from Hiding

If the Attacker is Invisible (Hidden and unknown to be there by the Opponent):

the Attacker gets Advantage on their Attack (this can be any time in the battle, not just on the first round)[1]
their Opponent attacks a still-Invisible target with (at best) Disadvantage.[1,5] If where the Opponent says they are attacking is not where their target is, the attack automatically misses.[5]

Note that if the “Invisibility” only comes from being behind Total Cover (the Attacker has not taken a Hide action, too):

the Attacker will not get Advantage for their attack
the Opponent can’t see them to target them in turn

The Attacker’s “Invisible” condition from Hiding ends immediately after an Attack roll (or a Verbal spell, or making a sound, or if the Opponent finds them).[2] (In other places it says after an “attack hits or misses,” but I think that’s effectively the same thing.[5])

Which, as written, implies that an Attacker with multiple attacks (e.g., Fighters at 5th Level) only get that Advantage to hit on their first attack roll, not on subsequent ones. The condition ends after an Attack roll, not an Attack action.
If the Attacker wants to get “Invisible” again, they must duck behind cover and do another Hide to regain that “Invisible” condition.[2] Just moving back behind Total Cover would give them physical protection, but the Opponent still knows they are there, so the Attacker won’t get Advantage on their next attack (“I know he’s behind that tree so I’m keeping an eye on that”).

Certain spell effects, like Greater Invisibility, can cause the Invisible condition to be instantly restored, or never actually lost, without having to Hide; these are a really annoying complications, just saying.

Net-Net

Is all this complex? Yeah, especially given player and DM cleverness and the wide variety of spaces and situations to which it could apply. Could it be simplified? Maybe, but only by handwaving more and more things that “should” be considered important in a combat.

I’ve tried to tie the material above to actual rules, but there is some DM interpretation going on. If you aren’t sure, discuss it with your DM first; they may have different interpretations than I do.

Would you like to know more?

Here are the rule links for the [footnotes] above.

D&D 5e/5.5e Rules – Ready!

The Ready Action is handled differently than in earlier editions, which leads to a certain amount of confusion.

Know the Rules Part of an ongoing series of 5e (2014) Rules notes. See the end of the post for notes on 5.5e (2024) rules.

It’s not always possible (or best idea) to just attack-attack-attack. Sometimes you want to … take some time, to seize the right moment, to make sure you understand the situation and can best act on it.

That’s what the Ready Action is for, probably one of the most confusing actions for new (or new, veteran) players.

So, what is the Ready action?

Part of the confusion here is that previous D&D versions have had the concept of “holding” or (4e) “delaying” a turn (“I’m going to hold until the wizard lightning bolts that guy to see if I need to hit him again or go over and help the rogue”). 5e reframes and reduces that concept to Readying an Action. It’s much more constrained as (a) it requires defining a trigger-response pairing, and (b) if the trigger doesn’t happen, your Action for that turn is lost.

Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready Action on your turn, which lets you act using your Reaction before the start of your next turn.

So an important couple of things here. First you are waiting for a particular circumstance, and second, you are not only using your turn’s action for Ready, but it will depend on you having your Reaction left in order to use it. And if the circumstance doesn’t occur … you’ve essentially “wasted” your actions for the turn. (Yes, “they also serve who stand and wait,” but it’s still kind of disappointing.)

A different way of looking at a Readied Action is that it’s a called Reaction to a specific circumstance (vs a canned Reaction such as an Opportunity Attack or a spell that can be cast as a Reaction). You don’t so much declare an Action as declare a Reaction you are going to take before your next turn. (I wonder if it would be a bit less confusing if they called it “Ready Reaction” rather than “Ready Action”.)

First, you decide what perceivable circumstance will trigger your Reaction. Then, you choose the Action you will take in response to that trigger, or you choose to move up to your speed in response to it. Examples include “If the cultist steps on the trapdoor, I’ll pull the lever that opens it,” and “If the goblin steps to me, I move away.”

So the trigger has to be a perceivable circumstance. You can’t Ready an Action in response to something you are unaware of.

(Can you make some sort of Perception / Investigation / Insight check as part of that? Good question. The answer is no as an Active check, because that’s an Action (the Search Action, to be specific); the DM could let you do a Passive check, because that’s automatic. But, then, that whole Active/Passive check thing gets complicated, especially when combined with Hidden stuff.)

The Reaction to that perceived circumstance is then to either:

Take a single Action (if you are a high enough level fighter to have multiple Attack Actions, you can still take only one, because that feature can only be used on your turn, not elsewhere in the round), or
Move.

(Note: don’t wait until the goblin steps up to you to Move, or else they will get an Opportunity Attack on you; wait until the step within ten feet of you.)

When the trigger occurs, you can either take your Reaction right after the trigger finishes or ignore the trigger. Remember that you can take only one Reaction per round.

A Readied Action is binary: when the trigger occurs you must decide to take that Reaction right then, or decide to ignore it and the Readied Action goes away (though it doesn’t count as having lost your Reaction for purposes of other types of Reactions).

If you say, “If a goblin steps out of cover over there, I will throw my javelin,” then once the goblin charges out of cover, you can’t wait until it gets to as closer range to shoot: you have to take the shot right then and there.

When you Ready a Spell, you cast it as normal but hold its energy, which you release with your reaction when the trigger occurs.

To be Readied, a spell must have a casting time of 1 action, and holding onto the spell’s magic requires Concentration. If your Concentration is broken, the spell dissipates without taking effect.

For example, if you are Concentrating on the Web spell and Ready Magic Missile, your Web spell ends, and if you take damage before you release Magic Missile with your reaction, your Concentration might be broken.

This is also important; a Readied spell burns the spell slot, whether or not the Reaction is triggered or you choose to let it be triggered. For this reason, a lot of magic-users only Ready cantrips, since nothing is “lost” if it isn’t used.

So, in summary:

Attacks are limited to a single attack, as with Opportunity Attacks (in both cases you are using a Reaction). Even if you normally get three attacks on your turn, you can only Ready one attack. The Extra Attack ability notes that it only applies on your turn. Read more about Actions and Attacks here.
It only allows Movement or an Action (not a Bonus Action, as Bonus Actions only occur on your turn).
That said, even if you are using Ready for your turn’s action, you can still also Move and take a Bonus Action. So it doesn’t mean you are completely paralyzed.
You only get one Reaction between turns. If you make an Opportunity Attack, or any other Reaction (like Counterspell) before your Readied Action triggers, you lose your Readied Action (and vice-versa). Conversely, if you managed to use your Readied Action, you cannot take another Reaction.
Readied spells actually burn the spell slot (if any) upon Readying, and require Concentration to hold onto until the trigger occurs (if it ever does), interrupting any other Concentrated-upon spells and possibly being lost if you fail a required Concentration check before it’s triggered.

What conditions can you Ready for?

To my mind, the “perceivable circumstances” for the Readied action require a something you can focus on — a place, a person, a proximity.

Examples that seem to me to be legit Readied (Re)actions

(beyond the ones mentioned in the actual Ready text above):

If an opponent steps into the doorway, I will Flamebolt them. [place]
When that archer steps back out from behind the tree to shoot me, I will shoot them. [place]
If an opponent steps next to me, I will hit them. [proximity]
Once the paladin engages an opponent, I will shoot their opponent. [person] [Rogues, this could allow a Sneak Attack, as that is allowed on any turn, not just yours.]
If an opponent steps onto the trap door, I will pull the lever. [place]
If an opponent gets within ten feet of me, I will run toward the door. [proximity]
Whichever of the two people I am standing next to first has someone step next them I will attack their attacker them. [person]
If Bob gets out of that cluster of bad guys, I’ll drop a Fireball there. [place]
If the guard pulls out her sword, I’ll stab her. [person]

Examples that seem to be to be too broad or complex or rule-bending to be an Readied action:

If an opponent steps next to me then I will Disengage and Move toward the door. [You can act or you can Move. Disengage is an action, and does not include actual movement]
If an Orc comes through the door, I will Flamebolt them. But if it’s an Orcish captain, I’ll Fireball them. [You can only prep one spell, and discernment as to Orcish rank is probably more complex than than you can take as a Reaction.]
When the Orcs arrive, if I am attacked I will Dodge, but if not, then I will Help my neighbor [You can’t plan more than one action or circumstance. Just Dodge instead.]
If an opponent gets within ten feet of me, I will Dash away. [Movement from a Ready is only up to your normal full movement, and is an alternative to taking an Action; Dash would be an Action, but it doesn’t actually move you, it just changes how far you can move.]
If people come out of one of the other three doors into the room, I shoot them. [Unless the doors are right next to each other, that’s too much to keep track of for a trigger; I tend to rule that focus of that sort is, at most, across a 90 degree arc, or about how broadly you can really see without moving your head.]

Remember that you are not obliged to follow through on a Readied action; you have enough Reaction time to either do the Readied action or to abort it (which, for a spell, means the slot has still been used up).

Spells

Also note that, for Readying a spell, that takes Concentration to maintain the readiness (you basically casting but holding the spell), so any Concentration spell you have running would drop when you do so. This is true:

Even if the spell you are casting doesn’t normally require Concentration — it’s the Readying and holding of it that requires the Concentration.
Even if you don’t eventually fire the spell — it’s the Readying that burns the spell and starts the Concentration.

There is an interesting extrapolation that since a Readied spell is actually cast on the player’s turn, not on the Ready-triggered release toward an enemy, then Counterspell would need to be cast as a Reaction on the casting, not the release. Which is really weird as it implies that the attacker knows you’ve cast (say) Fireball before it actually goes off, and is especially pernicious with an attack of Readying / casting a spell outside of Counterspell range, then running close enough to be able to actually release it as the trigger condition. Counterspell already makes my head hurt with its causality issues, so I’m going to try not to think about it.

So why does Ready work this way?

The Sage Advice Compendium goes into a bit of detail as to why things were designed this way, vs. previous editions (esp. 4e) that allowed folk to simply delay their position on the Initiative list in a round. It doesn’t change gameplay, but it’s still kind of interesting to understand the design goals.

For a variety of reasons, we didn’t include the option to delay your turn:

Your turn involves several decisions, including where to move and what action to take. If you could delay your turn, your decision-making would possibly become slower, since you would have to consider whether you wanted to take your turn at all. Multiply that extra analysis by the number of characters and monsters in a combat, and you have the potential for many slowdowns in play.

The ability to delay your turn can make initiative meaningless, as characters and monsters bounce around in the initiative order. If combatants can change their place in the initiative order at will, why use initiative at all? On top of that, changing initiative can easily turn into an unwelcome chore, especially for the DM, who might have to change the initiative list over and over during a fight.

Being able to delay your turn can let you wreak havoc on the durations of spells and other effects, particularly any of them that last until your next turn. Simply by changing when your turn happens, you could change the length of certain spells. The way to guard against such abuse would be to create a set of additional rules that would limit your ability to change durations. The net effect? More complexity would be added to the game, and with more complexity, there is greater potential for slower play.

Two of our goals for combat were for it to be speedy and for initiative to matter. We didn’t want to start every combat by rolling initiative and then undermine turn order with a delay option. Moreover, we felt that toying with initiative wasn’t where the focus should be in battle. Instead, the dramatic actions of the combatants should be the focus, with turns that happen as quickly as possible

In short, the 5e designers decided that somewhat more elaborate, and limited, rules for Readying Actions would actually make the game flow more smoothly, quicker, and in a less complicated fashion. I can’t say that I disagree.

Does any of this change in 5.5e?

Not really, no. The text in the 5.5e (2024) Vocabulary is practically identical to the 5e rules quoted above.

D&D 5e/5.5e Rules – Initiative and Cunning Plans!

Not surprisingly, a bunch of heroes clustered in a corridor are not quite as coordinated as you might think.

Know the Rules Part of an ongoing series of 5e (2014) Rules notes. See the end of the post for notes on 5.5e (2024) rules.

So something happened in the game the night before I wrote this up that, at the time, I kind of blew through, but I wanted to give it some thought. This is, of course, just the sort of thing I have sometimes taken justified criticism for overthinking. But it’s a situation we’ve run into more than once, and I’d like to have figure out a rubric for myself to adjudicate against.

And, as a caveat, it’s always worth noting up front that time and combat in D&D are abstractions designed to turn the chaos of real-life combat into something manageable. While a level of verisimilitude is the goal, manageability always trumps that. Just as D&D is not a physics simulator, it’s not a great combat simulator (falling somewhere between an FPS and Chess).

When the slow guy is supposed to lead off the attack

So, here was the sitch: as the party crept up two different sets of stairs to the upper floor where the local BBEG had their throne room, the plan was that Theren the Sorcerer was going to begin combat by lobbing his Vitriolic Sphere into the center of the bad guys.

How should the combat have been sequenced? Even handwaving aside the question of whether anyone knew that Theren was going first (there was probably an excess of allowable coordination between the two subgroups, since they were going up two different sets of stairs and not using any sort of communication magic) …

Did Theren’s action take place outside of the Initiative order? Did his executing the attack start the combat so that’s when everyone rolls Init?
- (Short answer: no.)
Did Theren’s Init get changed to the top of the Initiative order? Since he’s the one initiating the combat?
- (Short answer: still no.)
Did everyone with Init rolls before Theren sort of get skipped over? (That’s what I did, but it effectively means that those higher Init rolls become low Init rolls, which is “unfair”.)
- (Short answer: it should have been “voluntary”)
Did everyone before Theren in the Initiative order (ally and enemy) actually get to go in some fashion before Theren did?
- (Short answer: it should have been that way, yes.)
And did it matter if the bad guys were surprised or not?
- (Short answer: Yes and No. But in this case they were not — the Baroness had perceived you coming up the stairs and called for you to come in and play.)

Warriors! Come out to play!

In 5e, combat takes place with the Order of Combat:

Determine Surprise.
Establish positions.
Roll Initiative.
Take turns in rounds of combat.

In short: Initiative is rolled when combat begins. You can not make an attack outside of Initiative.

So, no, Theren doesn’t get to bypass the Initiative roll, or have his Init moved to the top of the order, or whatever. (Some folk have house rules for this, but that creates its own problems.)

So let’s simplify the situation a bit and say that the top Initiative order, when rolled, was (leaving out other players and bad guy mooks):

20 – William
15 – Baroness BBEG (the enemy)
10 – Theren

The first question is: is there Surprise? This is determined before Initiative is rolled, technically, though I don’t think it makes a difference.

If you’re surprised, you can’t move or take an action on your first turn of the combat, and you can’t take a reaction until that turn ends. A member of a group can be surprised even if the other members aren’t.

So if Baroness BBEG were surprised by this attack out of nowhere in her throne room (ignoring the previous sounds of the battles below), it counters her Initiative to a large degree. The beginning of the combat can be handled this way:

William says he is choosing to Ready an attack if anyone runs up to the top of the stairwell before his next turn. He’s doing this to let Theren get that shot off as agreed, rather than running into the middle of the room and spoil the AoE plans. It’s essentially giving up his turn, but there you go.
Baroness BBEG is Surprised — she’ll effectively see Theren coming, but will be unable to act on her turn. After her turn occurs, she would be able to take a Reaction (if she had Counterspell, she could then use it against Theren’s impending attack), and she will be able to act normally at the beginning of her next turn.
Theren pops up and acid bombs everyone’s ass.

So Surprise mechanics make things simple(r), because they provide for higher-Init enemies to be locked in place (but ready to go next time).

But in the case of the game that triggered this discussion, there was no Surprise (the party simply wasn’t stealthy climbing those stairs). Which means that there is a disconnect between Intent (lob an Vitriolic Sphere before they can act) and Execution (oh, they acted before I could lob my Vitriolic Sphere, because they had better rolls on Initiative). Or, as one site I saw put it:

“If your player wants to stab the bandit in the face before he has time to act, that’s what a high Initiative roll is for, not a Surprise round.”

Without Surprise, it’s Theren starting to move for his guns first, but the other folk outdrawing him.

“But Dave,” you may say, “she couldn’t see Theren before he came up the stairs.” That’s true, but because she isn’t Surprised (i.e., she was aware of a threat, and so ready to act/react), she still is able to act first as she chooses, because her Initiative is higher.

This gets into the whole idea that 6-second Rounds are themselves an abstraction — if there are six people in the room it’s not that Person 1 literally goes in the first second, Person 2 in the second second, etc. It means that within that six second timeframe, Person 1 acts before Person 2, who acts before Person 3, etc. That doesn’t completely match reality, because not everyone is declaring their actions before they happen as in some games (so that higher Initiative folk know what is coming), but it is essentially how 5e abstracts “People running around and into each other with intent to do mayhem.”

So here’s what should happen (should have happened in this simplification of last night):

William does whatever he’s doing — Dodging, Readying an action, casting Spike Growth in the middle of the room to make sure that nobody runs away before Theren can act, whatever. He’s choosing to back Theren’s play, but still moves faster/before Theren does, because he has higher Initiative.
Baroness BBEG “Readies an action.” Because I’m the GM, you don’t get to know what it is (“Chuck my magic spear at the first person atop the stairs over there”). Neener-neener. But she declares this (whispering in the GM’s head) before Theren because she isn’t Surprised and has higher Initiative.
Theren reaches the top of the stairs and turns to cast his spell …
… and Baroness BBEG executes her Readied action (throwing her spear at the first person atop the stairs, Theren, which hits) …
… and, if still alive, Theren throws his Vitriolic Sphere.

(Note: one of the players reminded me afterwards that Theren was Invisible. This gets into Perception checks, Active vs Passive, etc., to deal with his footsteps and verbal components, etc. In which case she might have been Surprised or she might have been aware something screwing was going on and still chucked her spear with Disadvantage against an Invisible foe before Theren could cast his spell (which would then drop his Invis).

Note that Theren could have said, “Well, heck, they aren’t Surprised so someone might plan to attack me” and change his plans from what had been intended. Or maybe, despite his intent and the team’s plans, William might have taken their Action to attack or distract the Baroness, which might have led to another change of plans by Theren. While Initiative lets people act first, the structure of the game from that point means that people are aware of the actions taken previously by people with better Init, allowing them to revise their plans accordingly.

(In the Action Economy, there’s a significant advantage in going first … but after that, Initiative is like Time: just a way to keep everything from happening at once.)

The bottom line is

You can’t easily plan your way into something that is the equivalent of Surprise (“I go before anyone else does”) if there is no Surprise present and you roll a low Initiative. That’s what Initiative is kind of for — if you roll poorly, you go later in the round.
If the other players who would have gone first want to effectively skip/delay their turn (do a Dodge or a Ready or maybe even a Help), that’s their prerogative for the tactical situation.
The enemy is under no such obligation, and if any of them have higher Init than the “this is how I am starting this combat” attacker, they get to do their thing first (which may be standing there in Surprise, or may be shooting you under the table).

Han rolled higher initiative — Even if Greedo intended to fire first.

Here are some articles that touch on this — which, given the volume, shows this is something a lot of GMs fret about, though most of the scenarios here involve Surprise, which, as noted, simplifies the question a lot.

“We get ready to enter the room”

So there’s one more area where this kind of thing has come frequently into play, the “We arrange ourselves at the door and charge in” scenario, when the Doughty Fighters at front roll crap Init (because they used DEX as a dump stat) and everyone queued up behind them rolls better Init than them and basically have to:

Move through the Doughty Fighters (as Difficult Terrain, and potentially exposing themselves to attack, which is kind of why you wanted the Doughty Fighters to run in first).
Ready an Action to move in when the Doughty Fighters have and the space is clear (but not then being able to attack or anything, because Ready only lets you take a single Action or a Move).
Fire ranged attacks past the Doughty Fighters (if the angle through the door cooperates).
Waste their turn.

The bottom line there is: yup, those are kind of your choices when everyone in front of you is slower. Hopefully the bad guys inside the room are Surprised!

So what’s different in 5.5e?

The new 5.5e (2024) rules are fundamentally the same, but with a few differences that can affect the above conversation.

First, Surprise is handled differently. Rather than the sort of complex (and deadly) “Everyone rolls Initiative, but Surprised folk don’t get any sort of actions until their first turn, and then they only get Reaction(s) until their second turn,” instead, it’s “Everyone rolls Initiative, but Surprised folk do so at Disadvantage.”

Much simpler, and it still means Surprised folk may get badly hurt unless they have a very high Init modifier or roll really well. Especially if the folk on the Surprising side have managed their Stealth, successfully Hidden, and therefore get Advantage on their Init rolls.

5.5e also addresses the question discussed above: “How do we let the guy who’s going to initiative combat actually do so?” While still insisting on keeping everything inside the Initiative framework for combat, the new PHB and Basic Rules favor the combat initiator by allowing the DM to give them Advantage on their Initiative roll. The problem can still happen, especially if the party wants to give the first shot to someone who used DEX as a dump stat, but it doesn’t hurt.

Second, squares containing Allies/Friendlies on a grid map are no longer considered Difficult Terrain. That makes clearing the corridor into the room a lot easier, even if folk are not lined up by Initiative (which, technically, they can’t be anyway).