While I was in the light maze, I dropped the key to make space for some mirrors. :wall: AACK now I can't get it back, do I really have to go through the underground pass to finish the quest? Can you get the key back at all?

Try speaking to the head mourner, I don't see why he wouldn't give you a spare copy. After all the long wait at the beggining of the quest, is all about cutting keys.

Search the mourners desk for another key.