After the break, the guards scan Peter and are satisfied he's not a Trojan horse or anything, and the guard continues to hit on Etta, pointing out that he's been promoted to Level 6, and then he confides in her that he's got something to tell her.
He shows her a picture on a Future iPad thing of Agent Foster (also known as Henry Ian Cusick) and explains he was found in amber: "Your superior was a double agent. He was working with the resistance. He was with someone named William Bell," says the guard. Etta does her best to look the right amount of surprised/concerned, and asks what they did with him, and the guard says "That's above my pay grade" which is kinda funny since he just bragged for fifteen seconds about being bumped up to Level Six. He, glancing at a security camera, suggests asking Windmark herself, since he'll probably want to talk to her about it anyway.
Windmark, of course, is currently preoccupied with turning Walter's brain into applesauce. "These physics in your mind, they are also above your comprehension," says Windmark to a whimpering Walter. Windmark asks what the stones are for, and again what their plan is to defeat the Observers. Walter can barely speak. "Let down the walls. I am your ally." Aw, Windmark is the Ronald Reagan to Walter's Russian brain!
Etta and the friendly guard wheel the gurneys into Corpse Disposal Central, I guess, and the guard proceeds to loot Elias's watch. He's about to remove Peter's boots when Etta shoots him (giving him a "hey" to get his attention so he KNOWS she's about to shoot him, which is both reckless and bad-ass). She gives Peter an injection to wake him up, and he is instantly rarin' to go, and asks what happened to the guard. "Occupational hazard," says Etta, and a prouder moment Peter has likely never had. I mean, he never got to see her graduate from what passes for school in this dystopia, so shooting a loyalist will have to do.
Etta and Peter sneak down some corridors that for some reason don't have security cameras and have an awful lot of luck just in terms of not running into anyone, and then let Olivia in via a side door or back door. (Also no security camera, I guess, despite them having them at the front where they have armed guards.) They find the room with the central carbon monoxide generator, which extends several stories up. Peter explains to a surprised Olivia about the permanent one being built in Central Park, and then sets about cutting wires until the unit malfunctions.