You are already locked to Magister's Terrace?

Q u o t e:
So after I kill myself by accident in MgT, I release, run back and now cannot regain entry after only killing 1 boss, what gives? :P

This is currently a known issue and is being looked into, Bubs, but from what I understand there is a work around. You should simply need to join a group, then you'll be able to enter.

Edit: *glances at Orlyia* Oh, Hai!.