I am stuck in the Dark Tower on level 2 in the room with the four doors that have to be opened by hitting damage tiles on a separate island on the side of the room. I can get the first three doors open, but I can't get that last door open! I remember this was the part I stopped at when I was younger for like a year before I picked the game back up and somehow figured it out. Anybody know what spell I need to cast to get the &*%$ door open?