I'm not sure this entirely makes sense. I mean, why doesn't that mean Peter just sees stuff from Earth-2 all the time? But it's a little late to be arguing that point and at any rate they have a bigger problem: If it has already crossed into the other universe, there's no way for them to go to it, what with the bridge being closed.
And then Olivia reminds them that she's able to cross over and Nina concurs, since Olivia now has as much activated Cortexiphan in her system as the Olivia from the original timeline. So with Peter being able to see the ship and Olivia being able to reach it, they can do it together, says Nina, one of those great moments on Fringe where it's "We've never experienced this supernatural situation before but we will make ironclad proclamations on how to handle it."
Olivia doubts her ability to do it so Nina babbles some clichéd bullshit about how she's had the power all along. Good enough for me! Olivia and Peter exchange glances and then take off their ear protection, open the door and get ready to jump. Olivia tells Peter that if he's lost his mind, now would be the time to tell her. He smiles and tells the pilot to "take it to port, about three yards," and then he yells "Now!" and he and Olivia jump. You know, they could have taken a life preserver along in case it didn't work. Better to take one and not need it, then need it and not have it, right?
But it works; as they plummet, there's a flash, and suddenly they're landing on a shipping container on board the Talos. Peter almost slides off, having much more difficulty hanging on, thanks to his bum arm. Olivia helps him back up. "It worked!" he says. Olivia asks if he's surprised and he admits he is. Also surprising her; he lifted a handgun from the pilot, saying she can't be the only one who always gets to carry one.
SO they make their way below decks, through the menagerie with the hay strewn all over the floor. "I think this is his ark," says Peter.
Fortunately, they're in time to catch some of Bell's speechifying, which is still going on. He's reciting Yeats with his eyes closed, which gives Walter the chance to remove and the load the Luger from its display case, but before he gets a chance to use it, Olivia and Peter burst in, Peter with his gun leveled at Bell, who sniffs that he wasn't planning to have any humans. "What a troublesome species we can be, after all," he says, like those porcupine bats are going to be so simple to look after. Jesus, come to think of it, I'd hate to be the one who has to mop out the stalls in the Talos menagerie.