'Fringe' recap: I've Seen the Future, Brother, and It Is Murder
So Olivia is back to work in her new Fauxlivia identity at Fringe division. Walternate tells Broyles that they need to learn how Olivia switches between universes without consequence, and the only way they find out is if they run tests on her as a willing subject, which she won't do unless she actually thinks she's Fauxlivia. Olivia, by the way, isn't faking the Fauxlivia stuff; she really thinks she's Fauxlivia, but Olivia's bleeding through: she spots Peter (well, her memory of Peter) on the street. She spots Walter elsewhere.
The Fringe team's investigating the death-by-bus, because the same thing happened the day before, making it a real statistical anomaly. Agent Lincoln Lee's the one who picks up on the common thread of a Rube Goldbergian chain of events that killed the victims, because of the presence of a ballpoint pen on the scene in both cases - pens apparently rare to the point of being practically non-existent in this universe. Meanwhile, Alt-Charlie, meanwhile, wonders if Fauxlivia might not actually be Fauxlivia.
At the scene of a third accident that unfolds even as the Fringe team is there, Olivia spots the guy responsible (identifying him due to sexy-agent intuition or something), but he escapes via the roof of a passing truck.
The Fringe team eventually finds out the guy, Milo, used to have an IQ in the 50s but has had several Flowers for Algernon-esque intelligence-boosting treatments, and he's killing the people who want to cut off the medication that's making him smarter. They track him down, and he sets in motion a trap that ends with Olivia getting crushed under a forklift-load of cinderblock, but Olivia avoids it because of her actual unfamiliarity with this world, something that Milo couldn't possibly have predicted. Olivia doesn't realize this at the time, though. She needs a hallucination of Peter to explain it to her.