I would suggest making people be able to see if there is anyone at the targeted vent so you know if it is safe to go there like the real game does. I would suggest using camera points to do so.
have them be able to do the walk in thingy BUT they get the button to chose once they’re inside (so that you dont see sombody just hovering over a vent thinking whered they go)
(oh yea also put a cd for reentering vents)