So the best advice I can give is definitely having you as the 2nd and 3rd door tank due mostly in part to Ring of Peace. Not only is it wonderful for a mass interrupt on the last parts of the 2nd door, but when the big adds on the third door that drop the frost orbs (forget th name) are disarmed with it their Mortal Strike does laughable damage. On top of this your Mistweaver can put it on you again, and that door becomes much simpler. When those wear out you can still Grapple the weapon from one, and ask The Mistweaver to do the same on another. It ups his healing and you take less damage during so it's a win win. Best of luck to you