A: I like Larian, so wouldn't wish them harm lol. (Well, only a little for this boss fight.....

) And yes, I am joking.
B: He teleports into the booths if blocked.
C: Pulling the lever is no small task when surrounded.
D: Resetting the levers while he is beneath 50% isn't possible as he teleports into the booth.
I play on 360, PC might differ.
Basically we need to take him down the instant we pull the lever, or we are met with a cutscene the moment the levers reset.
I should add I stunned and blocked Raze and he still healed, the git.