Anyway, Olivia's response effectively shuts Peter up, so there's that.
Speaking of the source, Raymond has been sent to the bookshelf to find a book on differential equations, when a short burst of a siren outside draws his attention to the window.
He looks outside at the police presence in the neighborhood but is called back to the dining room by Kate, who's excited about something in her notebook. She doesn't get to tell him what it is, because he figures it's time to show her what he's got going on in the basement. He takes her downstairs, and she's stunned to see the equations and machinery -- and I imagine a good chunk of her surprise is due to the fact that, in her perspective, none of this stuff would have been in the basement this morning.
She asks him what it is, and he says he built it from her work -- her theories and constants. "Time chambers are possible," he says, adding it took him almost three years to build it. It's not perfect, he tells her; he can only get it working for 47 minutes' worth of time chambering. Well, it's a good first try for a time chamber, Raymond! He says it can't go longer without the finished equation -- that's what he needs her to do, so he can keep the chamber open indefinitely.
By this point, he can't help but have noticed the distinct lack of delight on her face. "Raymond, what year is it?" she asks him, and he tells her it's 2007 -- and that's all he says, so she asks him what year it is "out there," and he cops to being 2011 in real life. She's taking all this in with open-mouthed horror, like he just announced he has another family with another woman a couple of towns over.
Outside, an FBI agent opens the gate and approaches the front door. Since it's not Olivia or Peter or Lincoln or Broyles or any other of our intrepid heroes, we already know he's dead. Halfway up the sidewalk, there's a kind of shimmer, noticeable enough to attract the attention of the Fringe gang nearby. The agent himself doesn't seem to notice anything amiss, at first, but he's just at the front steps when he starts shouting in distress -- only his voice is muffled, like it's coming from behind very thick glass. We can't make out what he's saying, so let's assume it's something like, "I can't believe NBC is pulling Community from the schedule!" and then he's put out of his misery by instantly disintegrating -- evaporating into thin air.
After the commercial break, Olivia is slowly walking up the front path, whilst on the phone with Walter. When she gets as close as she's willing to, he tells her to spray the fingerprint powder. She does so, and the powder reacts with the huge invisible dome enshrouding the property. "This is a time bubble," he tells her, and if they're right and what's happening is originating there, then the immense power is what obliterated the agent. "You can't just walk from the present to the past, shattering the laws of physics," says Walter, in all seriousness. You can throw a switch in your basement and send your home back four years without any outward appearance, but walking into the invisible time bubble, THAT would be ridiculous.