Once I realized what he was doing I stood by the lever but left it on. When he got to aroung 20% health he started running for it. I THEN turned it off and he had to turn around and head for the other one. That gave me just enough time to get that last shot in to kill him. My summoned pets go where they please and could never block him so this is an alternate strategy if you are not strong enough to just kill him outright. I am level 30 by the way.
