I have finished the crypt; I went all the way to the four tombs after the asylum, talked to the guy and was given the symbol-thing, but I can't find my way out! If I go back to the dock area, there's no way out... if I try to leave under the Rat-Guys room there is a locked grate...what now? I would really like to finish this quest, please help! Thanks!
Catacomb

There is a lever on the wall in front of the closed grates under the water. One lever for each gate (that would be 2). Throw the switch, go out, go back up to the mummy's room, drop the elevator, go up into the secret room, walk thru till you get the the statue of Kerah, and bascially walk back out from there (don't go down the way where the broken staircase is..that'll just lead you back to the elevator that leads to the mummy's room)