Anyway, Walter briefly brightens up as he tells Peter that it appears as though all the people were just drained of energy, just like all the batteries. "It wasn't just their hearts that stopped beating. It was every cell in their bodies," he says, and then when Peter asks what could possibly do that, Walter's awkward again and says he has no idea.
Over at the federal building, Walter's going over surveillance tapes on monitors, telling Olivia that twenty years ago, a person walking through Boston for two hours showed up on an average of ten different surveillance cameras, but now it's hundreds. "Bad for privacy, good for us," says Olivia. Yeah, well, NOW YOU KNOW WHAT THE TEABAGGERS ARE ON ABOUT. Broyles shows the route that RoboCop took, and eventually he winds up at a café, where he spent almost forty-five minutes before leaving. "The guy kills a train full of people and then stops for a meal?" asks Olivia. Point of order! You know, you don't actually KNOW yet that this guy killed everyone on the train. I'm just saying. Broyles says the trail goes cold there, as the guy didn't show up on any more cameras, so Olivia heads to Café Wilusa to check things out.
There, an Anna Kendrick-esque waitress recognizes the picture that Olivia shows her, confirming that the guy was there that morning. "He comes in all the time. Weird guy," she says, explaining that he's always drawing on the napkins and the placemats: "Some kind of math, I think. To be honest, my higher math ends at calculating my tip," she says, so it's totally fair for her to call a guy "weird" just because he knows more math than just how to calculate two percent of something. Olivia asks if the dude ever pays with a credit card, and sure enough, he did. The waitress hands over the slip, and Olivia's got a name: Alistair Peck.
It's not too long before the FBI is kicking in Alistair Peck's front door, but the place appears to be empty. There are blackboards covered in mathematical formulae, though, along with math-covered papers tucked all over the place, and Olivia radios to have the Bishops sent up.
Walter, eyeing the equations, calls the formulae "extraordinarily complex," as though someone is ever going to obsessively wallpaper their apartment with pieces of paper saying "2+2=4."
"Physicists use diagrams like these to short-hand ideas about how subatomic particles behave. These are sublime," says Walter. Meanwhile, Peter's found Peck's astrophyics degree, in a smashed frame. "He teaches at MIT," he says.
Walter excitedly says that if he's looking at the formulae correctly, that Peck has taken Einstein's theory "and turned it on his ear." Walter says he only grasps portions of it, but it does confirm that Peck was dealing with tremendous energy "to do ... whatever it is he's doing."
So the FBI agents are loading boxes of stuff into vans as Peck shows up on the street, coming back from ... oh, let's say Old Navy. He decides to just stroll right into the house and asks what they're doing with his things, and instantly has just about every gun in the place pointed at him. Not sure exactly what he was expecting here.
Meanwhile, upstairs, Olivia warily eyes a table full of surgical tools, and Peter's reaching for some sort of album, when they get word that Peck's there, so they head downstairs. Somewhat unnecessarily (not to mention kind of hilariously) Olivia pulls her own gun on Peck, who has his hands up. I bet that Olivia's one of those people who strolls up and pushes the elevator button a few more times even though there are people already standing there.
We can see wires and metal poking out of his arms, and Peter says that that must explain what all the surgical tools were for. "What did you do to the people on that train? Twelve innocent people," she says.
Peck shakes his head. "Those people aren't dead, miss. Not permanently." Olivia's all, 'fraid so! And Peck says, "But they soon won't be. Although, others soon will be, I'm afraid." That kind of talk isn't exactly going to get the agents to put their guns down. Olivia orders him to get down on the ground, but he's suddenly too concerned with the agents taking his equations out the door. "Don't take my computations! They're meaningless to you. It is well within my ability to make it so that you are never in possession of the things I require," he says, cryptically.
And now Walter gets in on the action; up until now, he'd just been kind of watching, fascinated, and now he gleefully points out that Peck has implanted a "Faraday mesh" (also known as a Faraday cage). Peter, the only other supposed genius-level intellect in the room, has no idea what Walter's talking about: "A shield, to create a temporal pocket around your body, of course," says Walter. Peck seems somewhat surprised that someone there has some idea what he's actually done, and starts to shimmer and wobble, while Olivia futilely yells at him to stop whatever he's doing.
And then, suddenly, Peck's back on the train. And the panhandler is outside, and as Peck gets off the train the panhandler approaches him again. "I'm sorry you have to go through this again," he says, and keeps on going down the platform. And once again, the kid gets on, and starts to scream at the train car of horrors.
So here's what I don't understand about the time-travel as it's presented in this episode, so if anyone who's smarter than me and understands it can explain it to me, I'd appreciate it: this is the second time Peck has jumped back to the train car. He hasn't rewound time, as he clearly has memories of the first jump and will use his knowledge of the police investigation to elude capture a little bit longer this time around, but reinserted himself back in the time stream of the previous day. So: shouldn't there be another Peck there? Himself, from the first time he jumped back? I realize that this would theoretically set up one of those time-travel paradoxes, given that the jump kills everyone in the immediate area, which means that the first Peck is killed, but that would mean that he couldn't jump back again, which would mean that the first Peck wasn't killed, which means he could jump back again, etc. etc.
Anyway, we see again Walter writing the letter, and Peter calling, trying to coax him to pick up. We watch again as the Fringe team approaches the train car and Peter and Olivia discuss how weirdly Walter is behaving. We see a little bit more of Walter's arrival on the crime scene, as well as Broyles, who is handed the initial report from an agent who's interviewing the panhandling kid.
Walter on the train, talking about a collective heart attack. Olivia, asking why all the lights on the train are out. And then Broyles shows up to tell Olivia about the panhandling kid, only the information he gives now is that the guy was in a rain coat, and he touched the handrail, so they're dusting it for prints.
And when Olivia talks to the kid, he's able to tell her that the guy said, "I'm sorry you have to go through this again." The "again" gives Olivia and Broyles pause. And then Peter steps off to tell her about the dead batteries (this time he was actually standing on the envelope, like nice observation skills, Peter), and the crime-scene guys find Walter's letter to Peter again, and once more he claims it.
And now we start to diverge a little bit more, with Olivia at the federal building talking to Peter back at the lab, with him telling her that the victims were just completely drained of biological energy. And after she hangs up with him, Broyles tells her that the fingerprint they found matched a set that NASA has on file for a Dr. Alistair Peck. "He was classified as part of a think tank. We don't know much more than that yet," says Broyles, and Olivia points out that now they have an address for the guy, 412 Inma