Can a pit trap affect multiple PCs?

[Taed]

I'm a new DM and we're running through H1 _Keep on the Shadowfell_. Right as the PCs get into the dungeon, there's a 2x2 (10' x 10') pit trap. I cannot find a good explanation about whether it could affect multiple PCs or not.

On one hand, since PCs will be moving one at a time, it seems that only the first PC to step into one of the trap squares would have a chance of falling into the pit. So, PC # 1 moves, triggers the trap, and the other 3 PCs obviously won't walk into the trap spaces on their turn.

On the other hand, they're not in combat (yet), so if the 4 PCs are keeping a 2x2 marching order, it would seem that (at least) the first row of 2 PCs would have a chance of falling down into the pit. The movement turns are logically taking place in parallel, so even though the 4 players have separate turns, they're all taking place at the same time. If handled this way, then I assume I'd have all the PCs move before announcing the trap and seeing who gets affected. However, that feels a bit too "artificial" since the clock is turned back with a "you didn't really do that since you fell into the pit."

So, how is something like this handled? Would the answer be different if it were in combat where turns aren't so clearly in parallel where actions occurring earlier in initiative order can be reacted to by later PCS (namely if two PCs are attacking a monster and the first kills it, the second can use their standard action to attack a different monster)?

Thanks in advance for your answers / advice!

 

[1of3]

It won't really work for the reasons you pointed out: Turns are not simultaneous. They are turns.

You could have traps that only break down under a certain weight: two medium sized creatures. (Even more fun, when a decoy "flees" over the trap.) But still one of the guys would need to end their turn on the trap.

 

[Amaroq]

This is a case where you ask the party "Okay, what's your marching order?"

If they're 2x2, then yes, your pit affects the front two. If they're single file, then the pit only affects the leader.

 

[cdrcjsn]

It affects as many people as you think it should affect.

You can change the trigger condition to activate the trap when more than one person is on it, after 2 people have walked on it, or when a monster in the same encounter activates a lever trap, etc.

Whatever you think is fun.

But for a basic, level 1 pit trap like the one on page 87 of the DMG, the trigger condition is one creature stepping on it.

 

[Gruns]

Are you talking about the one with the (semi-spoiler) rats ?
In this case the PCs are just walking, as you said, with no combat or initiative going on. What's their marching order? If 2x2, then the front two should be vulnerable. That is, if they just say something to the effect of "We'll head south and check out that door". There's really no good way to determine if they even step on those squares, so as the DM you get to say they do or do not. There's no right or wrong answer. (Maybe there is buried in some rulebook somewhere) The point is to have fun, and I personally think this encounter is a lot more fun when the unexpected happens. "As you head south across the room, the floor gives way! It's a tarp! You two in the front- Make saving throws to avoid falling in! Everyone- Roll for initiative!"
Later!
Gruns

 

[Taed]

We went through this encounter over the weekend. I had everyone move their own minis, but only two squares at a time. I told them that was to make sure what they could see around the corners, line of sight, and so on. Eventually, two PCs walked over the pit trap -- one made their saving throw (and thus fell prone next to it) and one didn't, so down one went. One said that they were stupid not to look for traps and stuff when entering the dungeon! The monsters then swung open the door and got some free surprise crossbow shots! The PC who fell down was a fighter with excellent athletics and was able to easily climb out and join the fight. It was a nice start to the dungeon crawl.