Just a note on door camping. Enemies don't open doors so much as try to walk through them. If you're standing directly in front of the door, they'll try to path through, freeze after the door opens and they can't path through you and then take their actions. Usually this means getting reaction bonked, but that leaves your gal standing in front of an open door and vulnerable to fire from the rest of the goons in the room.
Stand to either side of the door and enemies trying to path through will not halt inside the room. Instead, they'll make it one tile past the door before they halt. This usually means they get reaction bonked, but now your gals are not (as) exposed to fire from the rest of their friends.
It can be useful to park a few gals like this to hold a door while the rest of your team maneuvers to sweep the map and secure the other entrances. Setup is important for a proper breach and clear. If you open the door and someone is facing the door with a gun, consider waiting a turn or sending in another gal from a different angle. Avoid the temptation to use up all TU's on one gal at a time, instead, take one action at a time before switching gals so it's like they're all acting simultaneously rather than one after another. Because of the way reaction checks work, you'll take less fire this way. If you can get a gal within CQC range of every (armed) target in the room, you should do that before you actually start with the bonking. It's really hard for them to shoot accurately with a nine foot tall muscle mommy parked over their shoulder.
If a target has a gun *and* a melee weapon, consider that the AI is a lot better at choosing weapons in reaction mode. If you try to bonk them in melee and miss, their reaction will prioritize their knife, which is bad. If you park your gal in melee range and end turn, they have a pretty good chance of trying to use the gun in CQC and wasting their shots, after which your gal will bonk them. Sometimes they actually just walk away when you do this, which is odd. Consider whether your target has access to grenades. The AI will prioritize using a grenade if two or more of your units are close together, even if the guy throwing it is in CQC. Trying to double team one of these guys for a capture can often have the embarrassing result of them dropping a grenade at their feet, injuring two of your gals and depriving you of a captive.