Season 2, Episode 3:
Fracture
In Philadelphia, an on-duty cop gets a call from a man he calls "Colonel" to pick up a briefcase at Suburban Station. As he does so, a nearby pulse causes electronics to gain static, and his body becomes hardened. He explodes, killing eleven people and injuring others with his hardened body parts. Initially thinking the explosion was caused by a bomb, the Fringe team arrives to investigate, and discover that instead of a bomb, the cop's body parts killed the others. A further autopsy reveals needle marks between the cop's toes, and they realize he was injecting some type of drug every day for at least a year.
While Peter and Olivia interview his wife, Olivia gets sick with flashes of crossing to the alternate universe, and accidentally discovers the drugs the cop was injecting. The cop had served in Iraq for a year, and was involved in a secret military experiment called "Project Tin Man". Peter tells them they can find the project's doctors, and he and Olivia travel to Iraq. Peter learns from an old acquaintance the identity of one of the Iraqi doctors; he tells them the project was meant to cure soldiers exposed to a fatal chemical, but it failed to work, instead turning remaining survivors into human bombs. An AWOL colonel, Raymond Gordon, was opposed to ending the project; Peter and Olivia suspect he is behind the cop's explosion, and caused the deaths by emitting a radio signal. They find a list of names from the experiment, the victim in the train station being one of them. They return to find the surviving members, and are able to prevent the next subject, Diane Burgess, from exploding after she is contacted by Gordon to take a briefcase at a train station. Peter and Olivia find Gordon at the station, and bring him into custody; the man suggests the bombs were intended to eliminate agents working for the Observer.
Olivia and Sam Weiss continue to meet at the bowling alley, where he subjects her to seemingly menial tasks like tying her shoes and keeping score during games. Although initially finding their conversations useless, he cures Olivia's inability to walk without a cane by the end of the episode.
