Meanwhile, Peter and Astrid are discussing the situation, and Peter has floated the possibility that Bell would let Olivia die just to go on living. He's not entirely sure, but still: "On the list of accomplishments for William Bell, cheating death would certainly rank No. 1." Astrid's skeptical but considers it nonetheless.
The scientists come back in (Bell cutely, coming from Olivia's body, calls Astrid and Peter "kids") and say they think they've found a way to bring Olivia's mind back and remove Bell's: whole brain emulation. Naturally, it's another one of Bell's old projects, one that describes how an inorganic host can house organic material -- they've got an old computer, and they're going to put Bell into it. Or, rather, Walter is delegating that task to Astrid. "It's very self-explanatory," he says, not helpful at all. The scientists leave, forcing an extremely confused Peter and Astrid to chase after them, all "what the fuck?"
Walter says they're going to enter Olivia's mind in a "simple variation" of what they did when Olivia and good 'ol John Scott shared a dream state. Man, ex-boyfriends get brought up in the weirdest ways on Fringe.
All they have to do is tune their own brains to match the electric field of Olivia's. That's why Bell's looking for the neurosensors, over on the back shelf by the fish food. Peter, skeptical as ever, points out that entering Olivia's brain required an electromagnetic probe and mass quantities of hallucinogenics, and Walter is all, "Of course! LSD!" And now Walter is asking his son if he's "ever tripped" and then he's babbling about how Olivia's mind will be a maze-like iteration of her psyche, and since Peter knows her better than anyone, they need him to guide them. Without waiting for Peter to say OK, Walter's ordering Astrid to mix up two thousand milligrams of LSD, and they need some sugar cubes.
Then Walter drips some acid on the sugar cube, and tells his son not to be nervous, because "there are things in this very lab that are as mindblowing as anything that I've experienced while tripping." This could very well make Peter more nervous, not less, especially since he almost died once from drinking something he shouldn't have. Anyway, Peter eats the sugar cube with Walter explaining that he's added an accelerant to the acid so Peter will feel its effects sooner, and that once they're in Olivia's mind they should all be very cogent and I would just like to know on what he is basing THAT hypothesis. Anyway, he goes to help Bell and Astrid tells Peter not to worry; she'll be watching the monitors to make sure he's OK. Peter, a little choked up, says it's not himself he's worried about.