As almost every raiding guild knows, all bosses in The Eye are resettable by running out of the room except Kael'thas.
Well, mages can blink through the doors, just like they could blink through the bubble in EOTS.
Warriors can then cast Intervene on the mage and run through the door too. Now, when one of the people outside the room gets aggro, the mob will go past the door then reset the whole encounter.
Note: Other classes can also get out of the room by getting feared through by Lord Sanguinar, but this isnt a guaranteed method.