I have done it twice, both at the suggestion of the ldr, first time on the totem, second in the middle. Easy to do either role. I don't understand the need to do it though...doesn't really save much. Still need to activate the plate the same number of times. I guess with 4 ppl in middle at all times instead of 2, it is easier killing the thrall, knights and wizards, but if the plate person sucks, they are alone and if they die, its a wipe. Without the adds coming down from mid though, only the top knight should kill them, unless the mid ppl suck...at which point you have problems anyway and should develop patience or find a new team.