I got past the trapped corridor, and the room with the deathnight patrolling it, but the lefthand doorway to the upstairs area is locked and I cant find the key anywheres...
Fight the guards. Lieutenant will drop a key - open the small room in the guard's room there => lever. Right wall opens => 5 levers in there. Move 1-4 down AND up again. 5th lever calls a gargoyle.
