I got the "sacred key" Oct. 23 off a Ratman, practically right outside the Keeper's door.
The Keeper wasn't up, but it was nice to be able to peak inside the room to check.
ETA: Also got the key again Oct. 24 from another Ratman out in the courtyard. The ones with bags attached to their belts seem to be the ones that drop (which someone has probably mentioned elsewhere, but now it's here, too).
Edited, Tue Oct 25 13:04:01 2005