Peter wants the doodad to come off Walter right now and they pull it off, much to Walter's annoyance. "I'm not an amateur, Peter. I need this contraption if I am to retrieve the plan to defeat the Observers from the depths of my memory."
Peter points out that they don't even know if there's anything to retrieve, or just what that device might be doing to him. Walter ignores him and starts muttering in Swedish, but it doesn't sound anything like the Chef. Astrid tells a surprised Peter that Walter was speaking Portuguese earlier.
Olivia strolls in and Etta says she hopes the floor wasn't too hard. Young lady, your mother has been encased in amber for twenty-one years! Give her your damn bed! Olivia asks how things are coming along, and Peter says they don't know anything other than that at some point in the past Walter knew both Portuguese and Swedish. Walter, getting frustrated again, rips the thought unifier from his head.
As usual, Olivia's the one who gets right down to business and points out to Walter that he's always documented things, so is he absolutely sure he didn't write anything down? Walter can't remember, but he says anything's possible. Etta says even if there are files, they can't go back to Harvard, because they can't get in.
You may recall that Walter has been known to squirrel things away all over town, not just in his lab, but never mind. The plot reason is that the Observers took over Harvard five years ago. Oh, sure, but if people ask for human-specific scholarships, they're the racists, right? Oh, they're not attending. It's some kind of base, or, "no one knows exactly," says Etta. Walter says the Observer takeover is "not a problem for someone who's done acid," and Etta stares at him with a half-smile. Yep, that's your grandfather, kid.
She pulls up some sort of security camera feed that shows checkpoints around the building where Walter's lab is. "No one gets in without paperwork," she says. "Tunnels!" blurts out a giddy Walter.
So there are previously unmentioned steam tunnels under the building as, in fairness, there usually are under buildings like this. Hell, my own university had a network underground, so we didn't have to go outside to go to the cafeteria or to class. I'm pretty sure ours didn't have a secret entrance in a field miles away, like the spot Walter takes them to now and I'd kinda think that if the Observers were using Harvard as some sort of top-secret base they'd, you know, GUARD ALL THE ENTRANCES. Plus weren't they supposed to be some kind all-time-seeing-and-thereby-effectively-omniscient at one point... oh why bother.