I think the best way is to trigger something that kills the player so they know its wrong. I dunno if you can trigger a moving bomb to come in or something when abe kills a certain mud or slig?
Reason is that if you use uxb then abe can get mud to follow him into uxb and still die before he gets there. Maybe have another slam door that keeps that mud in the screen? Or dont lock door so they can go back and put him in the screen? I don't know.. I'm not a level designer as you can tell
