I did the nightfall (X3) with a couple buddies, and I noticed that the doors in the middle of the room start shaking when you kill malok. I also noted that your screen goes grainy if you try to go in beforehand. Like when you're out of bounds grainy.
We tried but couldn't coordinate in time to go one firetrap member to a door, but I think there's something to unlock in there. Anyone tried it? Can anyone try it and get back to me? I've read that you can get in on the story mode, I haven't tried it but I'd imagine it's just like the black spindle if it's anything. Maybe we'll have to wait until it's a heroic and try again?
-
Apparently it's a bug since you die by misadventure if you stay inside for too long. Seems to just be a spawn point for the adds. I've read that you can open the other doors from the inside if you get in, though.