More background from Munch, who spoke to Rook, who also hates managed care because his wife died in childbirth (and they lost the baby). Casey wonders why Rook never filed a medical malpractice suit, and Elliot doesn't figure a guy who's cool with making teenage girls suffer is going to let a doctor off the hook for killing his family.
Over to St. Mark's hospital, where we find that Dr. Slifkin died a few years ago in a freaky car accident, in which a semi took off his head. The official word was brake failure, but the nurse says she'd heard the doctor'd had one too many. She also remembers Rook, who insisted on a C-section, but the doctor overruled him but missed a complication that led to her death. The nurse says Rook threatened to kill Slifkin.
So the detectives delve into the case file; Elliot figures a smarty-pants engineer like Rook could easily tamper with brakes. Warner reviewed the autopsy and says the doctor's blood-alcohol level was .04, which wouldn't be enough to make the liver-cirrhotic doctor drunk. No sign of brake tampering either, and one of the forensics guys cues up the Pole Position-looking computer recreation, in which the doctor's car actually sped up before it hit the semi. So ... tampering with the gas? The death was ruled a suicide, since the doctor left a note and everything, saying he wanted to spare his wife: "Det. Milgram won't stop calling me. He says I'm going to prison for murder. I never meant to harm that woman and her baby. God forgive me."
In case everyone else is an idiot, Olivia says Rook pushed the doctor to suicide. So they'll dump his phone records, and that plus the note should be enough, right? Hold on, says the non-Warner forensics guy, who happens to be on Rook's website, which is exhorting the non-sheep to all go to Grand Central Station tonight for the most fun yet.
When Elliot and Olivia get there, there's no sign of anything going on, so they split up. Then, the leader of the Bryant Park rally yells over a megaphone "No sheep!" And several of the people in Grand Central freeze in place. Wow, consider my world sufficiently rocked, you guys. Way to make me question my conformist values. Olivia spots Rook, radios Elliot to come meet her, and tells him he's under arrest for the murder of Dr. Slifkin. Rook mournfully says he was a sheep and let the doctor slaughter his family.