Lee asks her if she thinks Jones has something to do with it and Fauxlivia tells him about Meana telling her that things were about to get a lot worse and then this happened. Walter says if Jones caused this, he's conceived of something Walter and Belly never did.
On to the testing! Walter hooks up a corpse to a row of tuning forks, because why wouldn't you? A low hum fills the air and Walter tells Lincoln and Fauxlivia that it's a perfect G. He shuts the machine off, then pulls from his satchel a plastic bag that contains a severed hand, startling the two agents. "I removed it from one of the victims on our side," he explains and Lincoln's all, "You couldn't bring over a casserole, but a severed hand is OK?" I'm sure the severed-hand prohibition is still working its way through the Bridge rules committee, Lincoln.
Walter hooks his machine up to the hand and it produces the same tone -- a G -- which he says is incorrect; it should be a C. "You see, each universe vibrates at its own specific frequencies [sic]. Everything from this universe would vibrate at a G, and everything from our universe at C," he says. Man, this is ridiculous even for this show, but Walter explains -- well, "explains" isn't really the right word, but what are you gonna do? -- that somehow the victims on our side were made to vibrate at the frequency of this universe. "So you're saying that the doppelgangers were somehow linked across universes?" asks Lincoln and Walter is all "Yes, it would seem so," but, um, DON'T WE ALREADY KNOW THAT? Fauxlivia asks how the bodies were retuned, because we are deep into some kind of Deepak Chopra-level bullshit here. Walter doesn't know, but he doesn't think it was the "retuning" that killed them -- rather it was the plane crash itself.
Lee asks Fauxlivia if they've recovered the black box yet and it turns out that this universe doesn't use cockpit recorders; instead, satellites record all flight communications.
And so we listen to the recording and from it we learn that the plane started coming apart and it happened very quickly. Walter says if his hypothesis is correct, then whatever merged the frequencies of the two universes destabilized the aircraft: "Whoever's responsible must have attached some sort of device to the craft." Fauxlivia's hung up on the why, though. It doesn't feel like an assassination. Is it a threat? What are they trying to prove?