I'm going to go right ahead and surmise that the corpse on the gurney being wheeled down the hall by a fetching woman in scrubs is at Boston General right now. She wheels him into a room where bodies are stacked in shelves like some kind of summer-camp nightmare.
The second she leaves, shutting the door behind her, someone unzips the bodybag from inside. It's Newton, beating Jesus' resurrection record by a few days. He sits up, pulls out his cellphone. Gasp! Does he not care that the cellphone can interfere with all the delicate electronic equipment at the hospital? He also has another one of those cylindrical things, and he pushes the button on top. A light starts flashing orange.
Over at the Bishop place, Peter gets off the phone with Olivia and lets Walter know that Verona turned out to be a bust. Walter, angrily slicing some bread, gets more agitated, and Peter tells him that he needs to get some rest. Walter's too pissed at himself: "I should have been more careful with my initial dissection. If I hadn't caused so much damage, it would ... it could have told us everything," he says.
Peter tries to get Walter, who says what he did was "stupid and inexcusable," to try to stop beating himself up over it: "We're gonna figure it out, just like we always do, OK?" After some prodding, Walter seems to accept this. "I want you to get some rest, Dad," says Peter, patting Walter on the shoulder before heading off to hit the sack himself. Of course, Walter brightens up and tells Peter that he just called him "Dad." "Yeah, I guess I did," says Peter, and he smiles, and turns to go but all of a sudden Walter's memory has been triggered, and he says he thinks he knows what Newton's going to do.
So Olivia is summoned to the Bishop house, where Walter starts babbling about how he and William Bell used geometry and harmonic vibrations to send Bell's car from this universe to the other one, because the two universes vibrate at different frequencies. "So we set up three harmonic rods arranged as an equilateral triangle and then activated the rods." He's setting up a little demonstration using a dinky car and the three identical tuning forks that no household should be without. "When the car began to vibrate at just the right frequency, that's how we sent Belly's car to the other side." Ridiculously, the car vibrates and then propels itself forward. Oh, now it seems plausible! Peter points out to Olivia that this is exactly what Newton did with the building. "But Newton's attempt failed," says Olivia, and Walter says that's because the building he brought over landed in a location that was already occupied by another. But he thinks Newton's found a way around the problem, because he's got something Walter and Bell never had: agents in both universes. "So if we set up the harmonic rods in exactly the same position in each universe like so," says Walter, while Peter sets up THREE MORE TUNING FORKS. Did they get the tuning fork Valu-Pak at a quick trip to Costco or something? Anyway, Walter says whatever's in the centre in each universe will simply be exchanged. To demonstrate that, Peter and Walter just ... trade dinky cars. Thrilling! You guys get an F at the science fair. "Of course, that would likely require that the universes be in sync." Olivia points out that that's at 3:31 this afternoon, and asks what Newton could be bringing here. "Last time he brought a building, so I suppose anything he could fit inside it ... a machine." An army, says Peter, ever the optimist, and Walter says that's possible, if the triangle is large enough. So they've got ten hours to figure out where the centre of the triangle is, which could be anywhere.