In what order do multiple readied actions with the same trigger resolve?

Question

My players have been scheming with rapid entry tactics for the megadungeon I've recently started running. Unfortunately, the monsters are aware of the adventurers, and this has lead to a weird question of priority. Given the following situation (which I'm pretty sure is going to happen next session in some form or another) what happens?

Alice the adventurer readies an action; if her teammate Carlos opens the door, she's going to throw the alchemists fire through the door, which should do enough damage to kill any goblins hiding there.

Meanwhile, on the other side of the door, Bob the goblin is lying in wait. He readies an action; if the door opens, he's going to hit the switch to open the trapdoor in the next room, which should drop any pesky adventurers into a pit with spikes at the bottom.

Carlos opens the door.

I know what happens when one readied action triggers another, but what happens when multiple readied actions get triggered at the same time? My guess would be an opposed reflex save or initiative check of some kind to see who goes first, but that's entirely just intuition speaking. The rulebook doesn't seem to speak to the issue.

Answer 1

Roll for Initiative.

While that may sound a bit counter-intuitive, consider this: ready is a combat action. Furhtermore, it is a special initiative action. It messes with the initiative order of things; out of combat there is no initiative order to mess with.

Then let's take a look at Dungeon Master's Guide, page 22, Starting Encounters section.

An encounter can begin in one of three situations.

• One side becomes aware of the other and thus can act first.
• Both sides become aware of each other at the same time.
• Some, but not all, creatures on one or both sides become aware of the other side.

Does the party know about goblins beforehand? No, they are not sure whether there are any behind the door.

Does the goblin know about the party? No, they could come at any moment. He is just a good guard and is ready for complications.

In this situation there is no encounter until the door is opened. As soon as it is, the encounter starts. Alice and Carlos see Bob immediately unless he hid himself, and likewise Bob, waiting for adventurers, is immediately aware of them opening the door. As the next page in DMG says,

Both Sides Aware at the Same Time:

If both sides are aware at the same time and can interact, both should roll initiative and resolve actions normally.

So, roll for initiative!

Possible complications:

• Since Alice the adventurer is going to throw the alchemist fire anyway, even if there is no goblins, I would rule that she "is aware of the other side" even if Bob the goblin successfully hides and is not detected.
• Goblins are not really the epitomes of discipline. Is Bob the goblin really patiently waiting for the giant invaders from above the earth, or is he busy eating a juicy rat which he had just caught?
• Perception checks from either party can make them aware of the opposition before the door is opened. In that case, use the both sides aware but cannot act immediately case (where simultaneous ready actions should be resolved as initiative ties are) or one side aware first, time to prepare (where the second side is surprised and cannot act). Remember that Alice probably counts as aware anyway.

Answer 2

An initiative roll seems appropriate for this. With only two people acting, it has a similar feel to a surprise round.

However, if I think about it along a more realistic standpoint, the players should be able to synchronize their actions (counting down to when the door gets opened etc.) The goblin is forced to react instead, so would go shortly after.

One last option that comes to mind is having both actions take effect. Alice throws the alchemist fire while Bob hits the switch. The goblins get hit by fire and the players get dropped into the trap.

Answer 3

The Rules Don't Say

Even the rules compendium is silent on this.

My advice is to resolve this tie the same way a normal initiative tie is resolved:

If two or more combatants have the same initiative check result, the combatants who are tied act in order of total initiative modifier (highest first). If there is still a tie, the tied characters should roll again to determine which one of them goes before the other.

The reason why I recommend that is that it's already in the rules, it's straightforward to implement, and it's not something that is likely to fluctuate a lot during combat (unlike the initiative order, which will change as a consequence of all these ready actions).

Answer 4

Multiple readied actions with the same trigger occur on the same initiative, so I would argue Tridus' answer is correct, but I think you could make a case, that is the rules (since at this point, two combatants have the same initiative).

However, there is a fundamental flaw in the question.

Since step 1 of how combat works is roll for initiative, you know everyone's initiative. Since combatants are readying actions, at least some of the surprise round must have occurred.

Carlos starts to open the door on his initiative (in the surprise round or round 1 is not clear, maybe Carlos rolled lowest or delayed). Carlos does not finish opening the door, because a readied action occurs just before the action that triggered it.

Two readied actions are triggered on Carlos' initiative (rather, immediately before). Since two combatants are about to act on the same initiative, resolve the tie as normal (highest modifier, if still tied roll again to break tie).

If the goblin won, the trap goes off, and quite possibly the future is altered.

If Alice won, she throws Alchemist's Fire at a closed door before Carlos gets the door open. Probably not what she intended.

Strictly speaking, you can't ready an action when Carlos opens the door to throw something through it, since it isn't opened when the readied action takes place.

Answer 5

Since this situation isn't really covered in the rules I would start with the common denominator in both, the door being opened. Since it is tagged for the D&D 3.5 rule set I will use that.

Once the door is opened the encounter begins and initiative should be called for. Once the initiative order is established resolve the readied actions in the order of initiative.

For example: Alice get an initiative of 8 and the goblin on the lever has a 10 so the goblin goes first. In this case the goblin would go first pulling the lever triggering the trapdoor. If Alice survives she can then attempt her readied action.