Reese encounters a rare physical challenge in this episode, getting "his ass kicked" by a professional assassin described as looking like a young Chuck Norris.
The episode explores Finch's guilt. His interaction with Peck is a highlight, as he sees a younger version of himself in the analyst’s relentless pursuit of truth. It also features a guest appearance by Carrie Preston (Michael Emerson's real-life wife) as Finch's former fiancée, Grace. Person of Interest 1x22
The episode's title refers to the philosophical irony that Finch faces: he built the Machine to save lives, yet its existence now necessitates the death of innocent people like Peck to keep it secret. This creates a mirror between Finch and Peck, both being brilliant men who tried to do the right thing only to be punished by the "Surveillance State". Reese encounters a rare physical challenge in this