I appreciate all the help earlier, Packrat... I have just rec'd the Staff of Death and want to leave, but the grate to the entrance is down and I don't see a lever. I 've tried Spells Call of Home and Teleport numerous times, but they all fizzle.

You can get out, if you jump off the bridge. Just pick any passage. I don't remeber which one is the shortest route, but I think they all end up on the other side of the Grate.

Teleport will take you to your last portal in this scene (i.e. dungeon), and call of home only works outdoors -- double bummer!

But don't despair -- you can still get out any of the sides. IIRC, you can go towards G'Ezzerad Ra and stabilize the bridge that drops you in the water, then go back across it to the main entrance area.

IMHO, placing a portal near the entrance into the Skull Castle (inside the dungeon) is the most effective way of solving problems with the dungeon. You can teleport to your portal from anywhere in the dungeon.
If you are inside the dungeon already, then do as suggested above. Jump into the water pool, save the game and try the exits from there. (Warning! All exits are "one way".) Take the exit where you find "manbeasts" attacking you and a giant (Gos'hin). Take this way. Wrong exits (as far as leaving the castle is considered) are exits with vampires, a small maze and a spell casting machine.

I found I could not teleport to the portal at the beginning of the tomb after I had got half way in. You certainly can't get out after you have have seen Kerah. Don't want to spoil too much so that's it.