Monsters stuck in doortracks, walls or hanging off lifts

Any monster in doom can be stuck on a ledge. They must be forced to a ledge by attacking them; or they can move themselvaes to a ledge and get stuck. When they are stuck, they will try to move, but stay in one place. They won't be able to attack when stuck on a ledge. But some monsters, sometimes, even when stuck on a ledge, can attack you if you're close to them. But only if they have a close range attack (ex:scratch).If monsters are stuck, they can be pushed off and freed if a player or monster keeps attacking it towards the pit.