For a quick finish, head directly down the corridor and through the door at the end to battle the game's first Skeletal Witch for control of the pentagram. Fire resistance will not protect you from her spells, so have healing ready. Once you have the pentagram, activate a flight spell and go up through the high holes in the wall to the west, where you'll find the exit.
You do, however, probably wish to explore the side areas before going for the pentagram, since there are some quality items in this section of the dungeon, including a free level up in the form of one of the rare Glass Skulls.
