When we come back from commercial, we're on Liberty Island in the other universe, and Brandonate is showing Walternate that the machine started going goofy sixty seconds ago. Brandonate shows Walternate that the soft spots aren't closing, but getting worse. Walternate stares at the vibrating machine, and the faint swirl in the centre where Peter would go, and then he tells Brandonate to get him Fauxlivia.
Hope he feels like being spoken too with smugness and disdain, because that's what he gets from Fauxlivia when he points out that the drawing suggests she has a connection with the machine, that she can stop it. "They outsmarted you, didn't they?" she says. "They know you turned the machine on. So they put Peter in theirs, and now we're the ones that are gonna get destroyed." They both turn to look at the machine, where the centre swirl is starting to look a lot more human-shaped.
Back over here, Walter has decided that something is wrong, and the crew scrambles to get Olivia up to Peter, who is still shaking slightly. The machine then powers down, and Peter opens his eyes, delighting Olivia. Peter's equally happy to see that she's alive.
Then Peter concentrates and the machine's humming again -- "Are you doing that?" asks Olivia -- and then shimmering and popping into the hangar are the rows of desks and computers, not to mention Brandonate, Walternate and Fauxlivia, suddenly appear. Olivia and Walter take a good hard look at their doppelgangers, who stare them down right back, especially Walternate. It's a testament to the acting -- especially, unsurprisingly, John Noble -- that having the different characters face to face never felt like just one actor in two roles, but two different people playing different parts.
Peter steps down out of the machine. He looks positively giddy about what's going on, while everyone else seems gobsmacked. Walter and Walternate look almost like bighorn sheep sizing each other up just before they start smacking each other's head. "I understand now," Peter says to Olivia, and then he starts yelling to his father, who's getting face to face with Walternate.
He tells his dad that he understands now what the machine is capable of and where it came from: The First People are us! says Peter. Specifically you, Walter! And maybe Ella and Astrid, he's not sure exactly who sent the machine back. Addressing Walternate, Peter says he's seen doomsday, and it's worse than anybody can possibly imagine. Tell them about the canned steak! TELL THEM ABOUT THE CANNED STEAK! "This isn't a war that can be won. Our two worlds are inextricable," says Peter. No one else seems to be saying anything or even really reacting. If one side dies, they both die, he continues, so he's torn holes in both universes, leading here to this room: "A bridge, so that we can begin to work together to fix--" and here Peter shimmers and suddenly vanishes.