Bookwyrm627: I just checked from an old save and it's on level 5 in the SE corner of the map. In the maze-ish area that is up a ramp from the friendly ghouls (the other exit of that maze-ish area leads to a ledge above the big lava room with Judy), a tunnel deadends at a room with an open portcullis and a lever just outside it. If you go inside, the portcullis shuts and locks, and a dire ghost attacks you. There's another door in there that leads to a tiny room with a gravestone and some items (don't forget to check behind the grave). There are signs there telling you about this area, including a "do not enter unless you want to die", and another sign inside that talks about "Here lies Nolant, formerly sir, who was kicked from the order for killing young Endicott in cold blood" (paraphrased).
The dire ghost drops a key that unlocks the portcullis. I was wondering if you found this room, and if you did, how you got out without using the key on the portcullis. There are a few different ways to do it, but they involve things like Gate Travel or the Silver Tree.
Re: Princess: Whoops! :D
Otta96: Ok, I definitely have visited that tomb, but I don't remember how I exit, is it possible to open that portillicus without the key?
Sure, but not through the portcullis itself. I don't think there are any physical exits besides through that gate. The switch that is outside the room is around a bend, so you can't see it. Therefore you can't use a pole or a Telekinesis effect to use it.
Ways out:
1) Use the key that the ghost drops. This is probably the most obvious way, and the ghost dropping the key and the portcullis saying it is locked if you try to open it lead to the obvious "use key on portcullis".
2) Use a lockpick on the portcullis. I think you can pick a portcullis, though I haven't bothered with lockpicking in so long that I don't recall trying it.
3) Kill yourself. Starvation is the easiest, but throwing yourself at the walls to take damage should work too. Avoiding a game over requires having replanted the Silver Seed somewhere outside that room, but I figure that's likely anyway.
4) Use a Gate Travel spell or scroll. This requires that the moonstone be placed somewhere outside the room.
It is entirely possible that you used the key that time, and then forgot that it can be done by the time you hit level 7 later in the game, and possibly days or weeks later in Real Life.