Anyway, if we in the present were to collapse our end of the wormhole, then everything they put down it, will just weigh it down. Walter demonstrates, cutting the tube and sealing it, and then dropping more marbles into the pipe, dragging the sheet down, sending the toys tumbling into the hole too. "The result is like a vacuum, sucking all matter and energy into itself, consuming it."

Peter sums it up: "You wanna turn the wormhole into a black hole," he says. Well, technically Peter, you do and Walter is just indulging you. Anyway, how to collapse the wormhole, leaving a black hole "and a hell of a lot of destruction" on their side?

Anti-matter is the answer. "The batons that we got in Etta's apartment," says Peter. Or the ones you got from Broyles, remember? You know, like the one Etta used to force you guys to leave her dying body? Yeah, those ones. Peter goes and grabs one, but then points out he's still going to need to get close enough to throw one into the corridor. Well, you really only have to get within a hundred meters, really. And plus, at the end of the last episode you demonstrated just how far you can run in twenty-six seconds, so it shouldn't be that difficult, even as Olivia -- she and Astrid have just strolled in -- points out that the place is going to be crawling with Observers and Loyalists waiting for it. I'm hearing lots of problems, but no solutions!

Walter says that's where the cube comes in -- he says the swirls of static electricity right before the corridor opened is like a telephone ringing, a phone call from the future. "The cube answers that call and the corridor is opened," he says. "So we just have to answer the call first," says Peter. Look, at some point, these similes are a little too simplistic, right?

Olivia points out that they haven't even figured out how to turn the cube on, and Walter chimes in that Anil couldn't get the Observer to make heads or tails of it either. But what they haven't considered is that Peter is Mr. Grieving Bad-Ass now and says Anil has his way of doing things and Peter has his.

So he's packing up the cube and Olivia asks if he's sure about this. Peter says he's sure they can't let them finish the air-degradation system. "We have this opportunity now," he says. Olivia tries pointing out that this could put Walter's plan in jeopardy. Peter's all, Oh, great! Walter's plan! "A scroll with physics we can't decipher, a thought unifier that doesn't work, and a box of rocks from a mine," he snaps, heading out. "That's what our daughter died for so far." To be fair, they're pretty nice rocks! Peter says if they can do this, they'll have something tangible, a real victory -- one that could set them back years. This may seem like the hindsight of someone who's watched the episode all the way through, but setting someone back years doesn't seem that big a deal when you're talking about people who have, you know, MASTERED TIME TRAVEL.