So the watch the tape, which is showing Walter taking a bus south on Quincy Street to Worcester Union Station and babbling about the "unique and efficient hiding place for a critical piece of the plan to defeat the Observers," at least when the Nosy Neddy in the seat behind him isn't listening over his shoulder. "What we have done is we have opened a space in the membrane that separates the two universes. A 'pocket universe,' if you will," says Walter. It's undetectable to the Observers' instruments, says Walter, and many of the usual laws of physics don't apply. This may seem like a dumb question, but if this space is not detectable by the Observers, why didn't Walter hide THE WHOLE PLAN there? Walter also appears too distracted by a pastry shop to finish such seemingly crucial sentences as "Do not, under any circumstances -- is that raspberry filling?"
Walter arrives at the destination -- 167 Cedar Street, in downtown Worcester. Astrid, doing some quick checking, determines that 167 is in the "Q-9 district," which I'm sure we can all agree is much catchier than "Worcester."
On the tape, Walter's gotten past the crabby neighbor and has made it into 413, where he greets a man named "Donald" whose face we don't get to see -- just his torso -- before Walter hands the camera off to him. The room, in much better shape than it is today, appears to have an unseen mirror straight down the centre, because there's two of everything, completely reversed on each side of the room. Video Walter says their eyes are not deceiving them, that the effect is caused by light refracted off -- and then he says it's not important. JUST ACCEPT IT. I have to confess that I didn't notice the same thing was true of the present-day dust-covered version of the apartment on first viewing.
What is important, Video Walter continues, are the lines written on the apartment floor, which "denote the trans-dimensional demarcation." He takes the camera back from this Donald guy and says, "I realize, whoever you are, that this must seem very complicated. It is. Extremely." Ha ha! But Walter adds it will all become clear once they're safely inside.