Obviously the guy, in a white T-shirt with an X on the chest, knows that since Peter can't operate a razor he can't fly a zeppelin by himself, which is confirmed when Walter comes doddering in, wondering what's going on.
The dude asks Peter's name, and Peter tells him, and the dude says, "Nice to meet you." See, that's nice! You can always be nice, even when brandishing a flare gun! Then the guy grabs a parachute from the wall, and fires his flare gun at the inside wall of the blimp, tearing a hole in it. Clutching the parachute, he gets sucked out through the hole. Clutching no parachute, Walter gets sucked our after him, while Peter's hanging on to a support beam yelling his dad's name.
Walter hurtles towards the falling thug and actually manages to grab onto him -- but the thug just pulls his ripcord, and when his fault is sharply arrested by the parachute, Walter plummets once more, all the way to the ground. Instead of splattering, though, he wakes up, discombobulated enough for Astrid to have to soothe him. "Oh, damn. I'm back," he says. On the plus side, Broyles is freaking high, so you wouldn't have wanted to miss that!
Back in Olivia's brain, Peter is tying up the zeppelin right in the middle of a Jacksonville street, so I guess the empty fuel tank wasn't any kind of big deal? Bell assures him that Walter will be fine, because he has so much experience as a cartoon man in someone else's mind. "Who was that guy?" asks Peter, and Bell figures it's someone unpleasant from her past.
Bell looks around to get his bearings, then points in the direction they need to go, but they'll need a vehicle. He asks Peter if he drives a motorcycle, because he would LOVE to ride on a motorcycle. He starts walking, and then he and Peter argue about which direction to go in, because Bell assumes she'll be at the daycare, but Peter says she won't be, and I'd like to point out that they're in a world in which the Twin Towers are still standing and a five-minute drive from the Eiffel Tower. But Bell acquiesces, probably at least partly because Peter has spotted a motorcycle for them to ride.
Back in the Harvard lab, Walter has decided he might as well throw a few more circuit boards into the computer that's ostensibly going to hold Bell's brain. Broyles, still ridiculously high, stares open-mouthed as a cartoon bird lands on Walter's shoulder. He whistles at it to get its attention, and it works, and then he waves and makes that strange face where he shows his teeth again. Walter looks up, briefly, and then goes back to working on the Bellytron 3000, but he drops some sort of special tube and it's the last one they've got so he's got to modify something by cannibalizing a tube from his phonograph blah blah blah.