Well when heroes search a room, although their piece might be stationary, the instructions say the hero is walking around, opening things etc. If a hero searches for treasure in a room with a weapons rack and finds a shield, even if their piece is on the other side of the room, I (as Zargon) move their figurine adjacent to the rack and tell them what they found.
With that said, if that hero is "searching" the room and a Wandering Monster comes up, Zargon can just pull his piece from the corner, put him out in the open and throw a monster next to him/her.
When it comes to trapped chest, I would prefer the hero to be somewhat adjacent to the chest. Although the heroes are supposed to stop on the trapped space to disarm it, since a hero can't (or at least shouldn't) occupy the same space as the chest, I'd say just put him adjacent to disarm it, if he triggers it he gets hit with the poison needle or whathaveyou.
I would suggest the same when it comes to searching the chest. Or at least move the figurine next to it.