Hmm... I thought I talked him into kicking Irenicus his ass. You can convince him, that he lets all of you out (your party including the "insanes" locked up in spellhold). He'll get a better position as Irenicus gets kicked out by you
I did it that way (and it worked!!) Im killed him once to, but I can remember having problems with that door too. I managed it anyway, I can't remember how. And then, there's another option.....shadowkeeper. Get your key from that program. (saves you a lot of (wasted??) time)
------------------
I pledged my vows to Torm - Mirac Honorguard (Undead Hunter)