At the site of "Formerly Massive Dynamic," Simon's got a door's access code on a little Post-It, which is apparently all that's required to bust in. Walter's slightly giddy over the adventure they're having -- comparing it to The Guns of Navarone. As they stroll through the parking garage, Walter says he's got déjà vu: "I feel like I've been here before." Etta says he has and probably many times, but a long time ago. Walter sniffs that he hopes it was cleaner then, as "dust is revolting."
They're too busy making with the small talk to notice they've tripped some kind of electric eye, which alerts an agent back on Fringe who's working on a computer that looks as thought it survived a bomb blast. He alerts Broyles that there's been a break-in at the underground parking garage at Massive Dynamic. After determining that it wasn't a fault in the system, Broyles nods at the agent, which I guess is short form for "do what you gotta do" and then gets on the phone to Capt. Windmark.
Over at Formerly Massive Dynamic, another access code earns the agents access to Walter's brain sample, stored in one of those areas where the lit-up circular shelves pop out all cool and futuristic. Walter misidentifies his own brain tissue as "monkey feces" and then continues to talk about monkey feces while Simon issues instructions to Etta -- a mixture of saline and polysorbate 80 to transfer the neural tissue -- and to Walter -- take these pills. "Diazepam, mostly. They'll put you in a deep sleep, for ten minutes that will quiet your brain to allow the process to occur faster." What we're going to do is put you to sleep, jam this tissue back in your brain and ten minutes later you'll be all better! Walter calls Simon a "clever boy," which makes Simon smile. Simon explains to Etta the pretend science that will make this work, while Walter talks about how he once ate brains, which was sweeter than you'd think, apparently. It would pretty much have to be, wouldn't it? Oh and also he loves LSD, and he's delighted at the prospect of the brain solution being injected into the base of his brain.
Then he suddenly gets very tired and practically passes out on his feet. Fortunately, Simon and Etta manage to wrangle him into a chair.
And now he's sleeping, with Etta and Simon sitting and waiting for him to wake up. Etta asks what happens if it doesn't work and Simon says it has to. Then -- because you don't get Henry Ian Cusick if you're not going to use him -- he gets to deliver a monologue about his freshman year at Stanford (suuure -- casually drop in that you went to Stanford, Simon), which is when "the Purge" happened. It was 2015 and the Observers were going from house to house and dragging people out into the street and killing them and he figured out that that's why his parents sent him so far away for school; they were part of the resistance and they sent him away to protect him. That was the night they were killed. "And that was the night I knew I wouldn't give up until the Observers had gone."