The freeze flash mob ends as Elliot's making his way over, and he suddenly proves incapable of making his way through the actually-rather-sparse crowd. And Olivia's not where she said she'd be. Instead of taking out his radio, Elliot stands there looking around.
A swat team followed by the detectives bash into Merritt's apartment. No one's there. Chester shows up with train station photos of Rook leading Olivia out of the station, with her dumping her gun and cellphone in the trash. Elliot figures Rook had a gun on her and she didn't want to risk him shooting civilians.
Desperate to find where Rook might have taken Olivia, Elliot heads over to Aerodax to question Dr. Chang, who was the co-worker Rook didn't want to find out about the prostitute. Turns out they went on a couple of dates, including one memorable one where Rook took her to a jazz club to watch a friend perform. Then, when the friend played "Lush Life," Rook burst out crying and left. The friend came over later and apologized, saying he forgot he'd recorded that song with Rook's wife. "Juliet was a singer," says Elliot, and Dr. Chang says they met when Rook produced one of her albums, which is what he did before he moved into aerospace, over at Tone Down Records in Brooklyn.
Elliot heads there, not with a SWAT team, not with the rest of the detectives, not with any single other law-enforcement official. He finds an abandoned record company, and sneaks around until he finds Rook seated in front of a mixing board. Rook's impressed Elliot found him so quickly. At gunpoint, Elliot frisks him and asks where his partner is. "Or what, you're going to shoot me? Then I don't think you'll ever find her." Elliot, after some consideration, lowers the gun, and Rook says Olivia's right next door -- in a soundproof studio with a door that's wired with explosive (to which Rook also has a detonator). Wish you had some backup now, Elliot?
"What do you want?" asks Elliot. Rook says he wants to conduct an experiment, to see how far Elliot will go to save his partner. We can see now that Olivia has things clamped to her neck. Rook flicks a switch on the mixing board and tells Olivia that Elliot's there. She urges Elliot to do whatever Rook says. Elliot asks her if she's all right, and she says again for Elliot to do what Rook says, and Rook flicks the switch again.
Rook makes Elliot sit down, and then lays out the parameters of the experiment. Olivia's in a chair wired for electricity, and shocks can be delivered via the nifty little remote he has. "The Milgram experiment," says Elliot. "You've done your homework," says Rook approvingly. "Only this time, the shocks are real," he says. He then flicks off the light switch, so we can't see Olivia anymore, and pushes a button on the remote and Olivia screams. Well, I'm convinced. Especially since Rook said that was a soundproof room Olivia's in, so I'm not sure why we're hearing her scream. Elliot won't do it, so Rook does it again, and says if Elliot refuses again, he'll increase the length and dosage of the shock. And he launches into a tirade about cops abusing authority, and Elliot feigns sympathy for Rook loses his family. "I didn't lose them," says Rook. "They were taken from you," says Elliot, and Rook goes off the doctor who refused to be challenged, so he caved in, and lost his wife. "I sat there and held my wife's hand and watched her bleed to death!" he yells, and orders Elliot to push the button. Again, Elliot refuses, and Rook does it, and Olivia screams.