This is an interesting spot...

If you can get into the hall, you're most of the way there. (I had to give myself a sect change to do it! Ahem!)

Near that gaethzen that glows despite being stuck in a cage of bone under glass (how big of a charge did they give it before they put it away?) the door that leads to the office is definitely not the one you want.

Once you find that door and go through it (anyone can go through if they manage to get into the hall) well...

there you'll find 4 doors that maybe nobody has ever claimed?

Iocanthe
Doing stuff