Did you forget your seaside days? When Arthas was about to touch the blade, Mal'Ganis attacked him.
Why don't you chill out for a bit? Once this is done, Echo of Jaina becomes available to fight.
Jaina knows it's coming, just not when.
Saphire to diamond she gleams now, The Kirin Tor leader who comes, "Queen" of a kingdom now fallen, Marching to war's martial drums.
It didn't place a circle but all of a sudden I am through the blockade and up on the stairs.
Jaina concluded that, since she had Darnassus on lockdown, it had to be someone who personally knew the Kirin Tor's portal network, using it to aid the thief.
EDIT: Joined dungeon queue, left dungeon queue, and joined torghast 6 and it worked.