I've seen the corpses of scavengers I killed inside buildings, but I'm 99% sure those were cases of the bodies falling through the ceiling. They will definitely follow you into buildings if they have line-of-sight and you leave the door open, but I have also never seen them intentionally open doors.
So... it's possible to complete the mission by taking the enemy out one at a time, and ducking back into safety inside a building....?
As long as you keep in mind that all safety is relative, that sounds like a useful tactic to have in your back pocket. I wouldn't relax too much while indoors mainly because, if you're jumping in and out as an intentional tactic, that greatly increases the odds that you trap one inside and have a nasty surprise waiting when you reenter that building.