Quest Recurring Nightmare - Talk to Lilly to return to Oriath. bugged.

Hey,
if you kill the boss in this quest, but teleport out, walk there again, you can't talk with her because the boss room has no stairs or other way to bring you in this room. Mission not finishable.
My first post. Hope this is the right way to report.
It's in Act 2, The Rotting Core.