 FAIR: SPOILER: John targets victims who dont appreciate what they  have, or are indifferent to the suffering of others. So why poison  Zepp and blackmail him into killing two innocent people? Zepp has  treated John with respect, reminding the doctors that he is a human  being, not just "the patient". Though John is clearly insane, this  is completely at odds with his motivation. However, it is revealed  on Zepps tape from John, that John considers Zepp a voyeur. He asks  him how it feels to have someone watching him. He obviously has a  disdain for Zepps spying on Doctor Gordon.