22:45:13.959 Garrosh Hellscream Melee *** 657050
22:45:38.081 Garrosh Hellscream Melee *** 662583
22:45:53.346 Garrosh Hellscream Melee *** 649657
That's on a paladin (10% less base mitigation) but it's still on 10m, so twoshotting is not out of question with an unlucky EF not ticking between two swings (and their super low avoidance). But it's rather hard to get a full grasp why his swing range is that big with regular swings being considerable lower (450k as pointed out before). He can get 3k mastery or 10% ap from "wrong", passive aura mindcontrols (shaman, hunter) but those numbers are simply to big to explain those spikes. Warcry has no effect on him.
We're always running with a disc priest and with his whole damage outside of whirls on the solo tank he get permanent absorbs shield from smart heals, shell and pw:s which might explain some spikes during downtimes, but both wol & wcl are capable of filtering for absorb values.