“Reciprocity” FRINGE season three, episode eleven. An ancient machine known to “The First People” as the vacuum has been assembled at massive Dynamic. When Olivia comments that the machine is bigger than she expected it to be, Peter replies “just big enough to destroy a couple of universes.
The science team at massive Dynamic has been unable to activate the machine or identify any power source. One theory is that a missing component (stolen by the other Olivia) may have been the power source. The machine reacts unexpectedly to Peter’s presence in the lab.
For those of you who have not been following along, A blueprint from the other universe shows Peter at the heart of a doomsday machine. Walternate (alternate universe Walter Bishop) has been assembling the same device in the other universe. Peter is somehow the key and power source to the ancient machine. “The First people” is a book which describes a technologically advanced civilization which once existed on earth but was destroyed long before the reign of the dinosaurs.
Meanwhile the encryption has finally been broken on the data file left behind by Fauxlivia (alternate universe Olivia Dunham, “the fake Olivia”) Among many personal observations of our world the fringe team discovers a list revealing the identity of five shape shifters.
Several of the shape shifters have already been killed; leaving the Fringe team to wonder if Walternate has been silencing them to clean up loose ends. Peter Bishop has secretly been assassinating shape shifters identified in the file left by Fauxlivia. When confronted by Walter, Peter says he is tired of simply being reactive. He believes that his efforts have largely been futile because the data storage devices carried by the Shape Shifters have revealed no new information. Peter defends his actions by reminding Walter that the shape shifters are soldiers and aren’t even human. He has done nothing wrong in killing them.
Walter believes that the machine has changed Peter, noting that every relationship is reciprocal. When Peter touched the machine it touched him back: his contact with the machine altered him somehow … maybe even weaponized him.