D&D 5E Adjudicating "bursting in"

robus · Apr 3, 2016

I'm sure this has been covered at some point but my forum search came up empty, so apologies in advance if this is a duplicate.

Anyway - my PCs love to burst into rooms to give them an element of surprise. However this kind of "surprise" is not covered in the rules that I can see.

The last time this happened I rolled a dice to see how many of the occupants were actually surprised but that seemed a bit lame. Any suggestions on how to improve my adjudication of moments like this?

delericho · Apr 3, 2016

You're basically handling it correctly. Ideally, you should decide if the NPCs would even have a reasonable chance to detect the PCs before making a perception roll for them (since in some cases the answer would be "no"). But, otherwise, it is just a matter of granting the PCs surprise in this case.

Naturally, whatever ruling you use for the NPCs should also apply to the PCs when their enemies send assassins to get them...

pming · Apr 3, 2016

Hiya!

Depending on how game-mechanic'y you want to get, you could always just give a simple penalty to the 'other sides' initiative (like -1 if they are guards waiting for the next shift change...-2 if they are guards guarding in the middle of the night, -3 if those guards are extra tired, -4...etc...etc...or maybe even Disadvantage). You could also tie in the modifier to the lowest/worse Stealth check made by the PC's or something.

But, as [MENTION=22424]delericho[/MENTION] said above, you're basically doing it right. You, the DM, figure out something that works for your group and your own particular DM'ing style, and go with that. Personally I just up and decide if they are or arn't 9/10 times. That other time, I drop back to my roots and roll 1d6, with 1 or 2 indicating surprise...and I make the players do the same in those situations. Whatever makes most sense for an actual 'surprise round' type of situation.

^_^

Paul L. Ming

robus · Apr 3, 2016

delericho said:
You're basically handling it correctly. Ideally, you should decide if the NPCs would even have a reasonable chance to detect the PCs before making a perception roll for them (since in some cases the answer would be "no"). But, otherwise, it is just a matter of granting the PCs surprise in this case.

Naturally, whatever ruling you use for the NPCs should also apply to the PCs when their enemies send assassins to get them...

Yep - they're being stealthy as they move about (listening at the door to try and determine what's inside). If they hear voices then they're assuming it's good for a "surprise" attack, otherwise they open the door slowly and try to get a peek before entering.

robus · Apr 3, 2016

pming said:
Hiya!

Depending on how game-mechanic'y you want to get, you could always just give a simple penalty to the 'other sides' initiative (like -1 if they are guards waiting for the next shift change...-2 if they are guards guarding in the middle of the night, -3 if those guards are extra tired, -4...etc...etc...or maybe even Disadvantage). You could also tie in the modifier to the lowest/worse Stealth check made by the PC's or something.

But, as [MENTION=22424]delericho[/MENTION] said above, you're basically doing it right. You, the DM, figure out something that works for your group and your own particular DM'ing style, and go with that. Personally I just up and decide if they are or arn't 9/10 times. That other time, I drop back to my roots and roll 1d6, with 1 or 2 indicating surprise...and I make the players do the same in those situations. Whatever makes most sense for an actual 'surprise round' type of situation.

^_^

Paul L. Ming

That sounds interesting. What I've found if I treat all the monsters as surprised then they're generally getting cleaned out by the PCs before they even get a chance to fight back (hence the PCs preference for this tactic

). Providing some randomness should make things a bit more unpredictable.

Hriston · Apr 3, 2016

robus said:
Anyway - my PCs love to burst into rooms to give them an element of surprise. However this kind of "surprise" is not covered in the rules that I can see.

It seems to me this is covered just fine with the surprise rules. Ask the PCs to make a Dexterity (Stealth) check while they're outside the door and compare the results to the passive Perceptions of the monsters to determine if the monsters are surprised when the PCs burst in or if they hear something outside the door. Also ask them to roll for Initiative before they open the door since that's going to be the first hostile act.

robus · Apr 3, 2016

Hriston said:
It seems to me this is covered just fine with the surprise rules. Ask the PCs to make a Dexterity (Stealth) check while they're outside the door and compare the results to the passive Perceptions of the monsters to determine if the monsters are surprised when the PCs burst in or if they hear something outside the door. Also ask them to roll for Initiative before they open the door since that's going to be the first hostile act.

Huh, I hadn't actually thought of them as hiding, but you're right, they are. I was getting caught up on the bursting in part.

Hriston · Apr 3, 2016

robus said:
Huh, I hadn't actually thought of them as hiding, but you're right, they are. I was getting caught up on the bursting in part.

An argument could be made, depending on the construction of the door, or ambient noise in the room, that the door provides a superior form of obscuration, perhaps imposing disadvantage on the monsters' passive Perception, but it's essentially the same act of hiding that would precede most ambush-type situations.

DEFCON 1 · Apr 3, 2016

One thing I've starting doing (and will be using continuously now for CoS) is having PCs use 'Passive Stealth'.

Rather than having each PC make a DEX (Stealth) check just prior to them busting through a door (which then begs my question on if they actually TRIED to be stealthy, or didn't declare they were trying to Hide etc.)... I instead have all PCs record their 'Passive Stealth', which is 10 + DEX mod + Prof bonus (if they have Stealth) - 5 (for Disadvantage due to armor if applicable.) I treat this as their perpetual "We're walking carefully throughout the dungeon trying not to make any noise" check. I then compare this to the Passive Perceptions of any monster they come across who aren't actually alert or on guard. Any monster whose PP is higher than the loudest PC is not surprised, those who are lower are. By the same token, if the monsters are not doing anything purposefully loud (which would automatically be determined by me as being noticed by the party), then they also will have Passive Stealth checks that the party will check their Passive Perception against. So when the door is flung open, any PC or monster whose PP is higher than the lowest PS of someone else in the opposing group, that creature is not surprised and gets to act during the first round of combat.

Does that hose the really stealthy PCs? Yes and no. Technically, it doesn't matter how stealthy the best PCs are, because all that matters is that the group of goblins heard ONE of the PCs coming, and thus knew to jump up and grab weapons. For the stealthy PCs... it's only if they break out ahead of the rest of the party to scout do they get to make active DEX (Stealth) checks and roll the d20 to determine their really high DC for the goblin's passive perceptions (and thus quite likely get to take the entire group of monsters by surprise.) The only downside of course being that if they take that shot, they're out ahead of their party and have to deal with a round or two of the fight just being with them. So maybe it's worth it to do so for that free round of attacks with surprise... maybe it's not (if they don't think they can withstand all the return attacks.)

By the same token... the same way stealthy PCs can scout ahead and thus make active Stealth checks... any creature who is "on guard" or alert and searching for danger gets to make active Perception checks to hear the party coming (1d20 + INT + Prof bonus). So they have a 50% chance of getting a higher check over their standard PP. But this only applies to those creatures on guard and not to the rest of the monsters-- unless of course the PCs diddle-daddle and give the guard monster time to alert his friends that someone is coming.

Thus far Passive Stealth has been working well, as it gives me a constant baseline for how loud the party is as they walk normally throughout the dungeon. Makes checking them nice and easy.

S'mon · Apr 3, 2016

If PCs are aware of the monsters and burst in on unaware monsters, yes they get Surprise. But monsters can hear PCs sneak up. Monsters can lock and bar doors. Even unlocked dungeon doors can be stiff and require STR (Athletics) to kick/bullrush open. It should not be automatic.