From what I've always observed in the "water major complaint logs," it just seems that the foci attracts lazy asses who don't prep enough for the types of enemies they try to take on. Note the damage he was taking from regular hits. I'm guessing he had stoneskin and maaaybe shield or aura. Maybe. Plus he went after two people at full, or near-full hp. Just wasn't a wise decision and he paid for it.