So this came up in a game I was DMing. I am relatively new to DMing and would like to understand what the rules in this situation would be by RAW and what people would do if it were a game they were running.
The party has reached a door and wants to listen at it. On the other side of the door, there are some soldiers waiting to ambush them. My understanding of RAW is that this is going to come down to some Perception vs Stealth rolls. The question is what are the bonuses and penalties? I know there would be a -5 to the party's Perception for the door in the way, but do the soldiers get any bonuses for being in position and only trying to stay still and quiet? I can't find anything about Stealth and not moving, except in the case of being invisible where you get a +20 to Stealth. Are the soldiers no better at staying still and quiet than if they were moving at half speed using Stealth? No one can stand perfectly still and quiet so there is a chance they could be discovered, but from how I understand the RAW for Perception and Stealth the party is as likely to perceive the ambushers in this case as they would if the ambushers were moving around or breaking cover completely.
If there is no RAW bonus but I still wanted to give them one, what would be reasonable? The standard +2 circumstance bonus seems low, but +20 like invisibility gives seems unreasonable (and tied to the ability/spell rather than being a general rule).