Astrid comes in, saying the library wasn't open so she had to go to the bookstore. Olivia asks what for, and Walter tells her that when she's in the tank, she has to listen to his voice at all times. "This is a technique I developed decades ago in this very lab," he says, brightly, before adding, in a lower voice to Astrid, "Most of which I don't remember." This would be around about the time that I'd march over to Olivia, remove the prong thing, rip off the electrodes and say, "You know what? Give the twelve stages of grief a shot first."
Anyway, Astrid takes out her bookstore purchase, which is a bible. Peter doesn't elaborate; he just starts talking about how the last time she was in the sensory deprivation tank, she went into a state of shared consciousness with agent Scott, which was when some of his memories crossed over into her brain. It makes perfect sense! "By putting you into a state of deep hypnosis, and by giving you substantial doses of psychoactive drugs, I can help you to access those alien memories that your mind has repressed." He tells her that his voice is her guide: "But it is also your tether to reality." See, that should really be a red flag to Olivia: Walter Bishop saying the words "tether to reality." He tells her to focus on his voice, or she risks getting lost in the memories. Then he says, "Uh-oh..." Olivia's all, what? "I just got an erection," he says. You're not supposed to tell her, you dingbat! Walter notes Olivia's eyebrows are raised halfway to her scalp and tells her that it has nothing to do with her "state of undress," which I'm not sure makes it worse or better: "I just simply need to urinate." He gets a boner when he has to pee? Isn't that inconvenient? I mean, if I remember my junior high health classes correctly, doesn't the, um, standing at attention prevent seeing a man about a horse? "That's good to know," says Olivia, dryly, and Walter blithely goes back to some equipment and asks Astrid to get her in the tank. Yeah, and make sure she's got the correct prong in her, Astrid, if you get my meaning. She asks Olivia if she's sure about doing this again. Olivia lies back in the water and says she just wants it to stop, and if John's memories can do some good, then at least she wasn't deceived for nothing.
Walter, injecting something into her IV, tells her that she's going to feel sleepy and reiterates that she needs to listen to him at all times. "Concentrate on the name of the man from whom you seek the information. And look for signs," he says. Olivia asks what kind of signs. Walter waits a long moment before answering, then says, "I'll tell you when you get there," he says, rather gravely, so it's probably nothing as benign as hobo symbols carved into fenceposts. Already sounding sleepy, Olivia asks what the bible is for. As he stands above her, hopefully not hoisting the mainsail anymore, he says, "Well, you're taking untested psychedelics, lying in saline with an electrical charge in the base of your cranium. Among other things, I thought it appropriate to pray you don't get electrocuted." It's not too late to get the hell out of there, Olivia! She quietly says, "Praise the lord," and Walter says "Amen," and closes the doors.