Brian leads Dexter outside to the garage, where Deb is wrapped up in plastic, Dexter-style. She's still unconscious. "I've prepared her just the way you like," says Brian. "This time we'll do it together." Dexter moves slowly, unbelieving. "Does it have to be Deb?" Dexter asks. "It's the only way," Brian responds. "But she's my --" "Fake sister, I know. Tell me something. Your victims...are they all killers?" "Yes." "Harry teach you that?" "He taught me a code...to survive." "Like a...an absurd avenger?" "That's not why I kill." Brian tells Dexter he can be himself around him, which we know. I'm assuming Dexter heard that message loud and clear as well. "Who am I?" Brian asks, after a pause. "A killer, without reason or regret. You're free." Brian says Dexter can be free, too. He continues to try to convince Dexter that he doesn't really have a code, Harry did, and "he's been dead for ten years." Leading Dex over to Deb, he says, "You need to embrace who you are now." "I don't know who I am," says Dexter, seemingly on the verge of tears. Brian says that's because he's been away from his family too long. "I can help you. We can take this journey together." Brian reaches into his back pocket and grabs a Scientology pamphlet, and...oh, wait. That's actually not at all what happens. Looking down at Deb, Dexter says, "I can't. Not Deb. I'm very...fond of her." Brian yells at Dexter, "You can't be a killer and a hero. It doesn't work that way!" He grabs the knife from Dexter, and as he swings it down to stab Deb in the heart, her eyes open and Dexter's hand catches his wrist, stopping him. A battle ensues and Brian knees Dexter's face, dropping him as sirens approach outside. Brian takes off after seeing the police lights, and Dexter yells, "In the garage!" Doakes rips open the door with his gun drawn, and Dexter points him to the door Brian left through, which is locked. Doakes tells LaGuerta to cover the door and runs back outside. Dexter hovers over Deb, probably wondering how much she heard before opening her eyes.
Outside, Doakes breaks into the adjoining structure with an axe, and once inside he discovers an escape tunnel under a piece of sheet metal. Brian's gone.
Later, Deb is being examined by an EMT. "Any headache, dizziness?" "No, I'm fine," she says. She is definitely not fine. Even if she is right now, she's going to need some serious therapy. "I just want to go home," she says. "I'm afraid we have to transport you to the hospital," says the EMT.