when you finally get the red key and you go down 3 or 4 floor by the stairs, you arrive in a room or a sign tells us is that we must prepare spells. they kill a monster or two ... Exit this room and the wall bug, you can get through it and is missing because no one is more than open space and bugged. This is my backup kidding or the game ?
Unfortunately, I don't know.
Shoonay?