[Embers] door disappearing in Ureslak's Host

[NEHZ]

I'm currently in the Hidden Vault - Ureslak's Host (3)
After not finding a way forward, I tried to get back to an earlier junction in the level, but one of the doors that I came through has disappeared. Hitting Z claims everything has been explored and doesn't do anything. The staff of recall is blocked. My character can't go anywhere and can't even die (since I beat all the enemies).
Also, the game gets increasingly slow, so I assume something is spawning units.

[ibanix]

Submit your save to stunt, he can fix this.

http://te4support.org/ticket/open.php