After a commercial break, Walter is doing that thing he does where he seems impressed to the point of envy of some evil genius's scheme and explains that Jones is using the Cortexiphan kids to link to their counterparts in the other universe and blah blah blah "science" blah blah blah vibrations and frequencies bullshit. Walter says he has underestimated Jones. "The man must have a remarkable mind to devise a plan like this," says Walter. Yeah, not to mention EVERYTHING ELSE JONES HAS DONE.
Peter, looking somewhat pessimistic, asks Walter if the connection between the two universes could be what's facilitating the psychic link. Walter figures it's possible. "What if we severed it?" asks Peter.
Walter is appalled at the implied suggestion, but Astrid needs it spelled out for her: Peter's talking about shutting down the bridge, to break the connection between our Cortexiphan kids and their Earth-2 doppelgangers. Astrid asks if that would work. "In theory, yes," says Walter, which is hilarious because it's been all of about fifteen seconds since he said it's possible that the link is what's allowing this to transpire and now he's apparently going with the assumption that it is and is making further assumptions about what would happen if the bridge were to shut down.
Walter says if they shut the bridge down they won't be able to start it back up again. You know, until later when it becomes convenient plot-wise to do so and Walter figures out a way that's so crazy it just might work. I mean, why couldn't the turn the machine back on? Oh and Walter also says the healing that the other world is experience will likely stop. Things won't get any worse, but they won't get any better anymore. Why? Because shut up, that's why, apparently.
Olivia's got another idea: find Jones and stop the attack and they can keep the bridge open. To that end, they bring a very unsettled-looking Nick Lane from the other side and seconds later in TV time he's in the Harvard lab with a Walter Bishop head apparatus on and an IV drip. "Will any of this stuff hurt me?" he says and Walter -- rather unconvincingly -- is all, "Shouldn't!"
Olivia explains to him that she knew this universe's Nick Lane when they were kids and she's hoping to use his psychic connection to his doppelganger to find him and exploit the childhood bond they used to share. Earth-2 Nick is a little raised-eyebrow over this making sense to all the rest of them and Lincoln advises that he basically shut up and go with it.