If you are paladin, and you see someone else than you (or especially, someone else than tank) is going to eat a tankbuster (the WHM in question) can't you use Cover for it, and then try to peel him of afterwards. Haven't really played paladin much but I've seen them using cover in midas lately. My favourite is those in M1 who hit it right after the MT has got the tankbuster debuff. The attack hits like a noodle to undebuffed OT. (Some tanks also manage to make a tank swap between the debuff and the hit)