So everyone seems to wipe on the Bonus boss in HM Kaon. His adds spawn in his original position, not his current position. He also seems to have no (or atleast a very slow) enrage timer.
SO, what you do, is agro him and run him back into that casino room where the allied NPCs are. Kill him in this room, and you will not have to deal with the adds until long after he is dead. If you don't have enough DPS, kite him further.