Eleanor Shaw: The assassin always dies, baby. It's necessary for the national healing.
Eleanor Shaw: Oh, God! Where are all the men anymore? My father, Tyler Prentiss, never asked, "Is this okay? Is this okay?" You know what I'm saying, Mark? He just did what needed to be done.
Raymond Shaw: I served under him. He was a good man.
Eleanor Shaw: Well, that's what the neighbors always say about serial killers.
Senator Thomas Jordan: And you bring me rumors and conjecture.
Ben Marco: I started with nightmares. Rumors, conjectures, that's a giant leap forward.
Chosen answer: Perhaps the piece-of-plastic killing was a "test run" by the brainwashers to see if Raymond would actually react to their commands. You can see other soldiers lying down wearing "halos", hinting that this happened at a different time and place than the observation room choking.