Update

I checked the map in hammer and found it it really is just SFXs that play at random times when in the dark room, i also could see every trigger and dark figures, They're just normal half life 2 citizen models, But colored black in-game, and some even have animations, I also discovered that at some point near the entrance to the entrance to the dark room and mirror/white rooms, and i heard it in-game at some point, Really spooky.