Continuity mistake: When Doakes is about to be killed by Guerrero, the police save him by shooting Guerrero, giving him a bullet wound on his right shoulder. He is also cuffed on the ground to be arrested. However, when he is pulled up, Guerrero does not have a bullet wound anymore.
Trivia: (POSSIBLE SPOILER) When Masuka brings up the list of doctors authorized to get the M99, Dexter removes his alias note that Dexter's fake alias (used to get the M99 tranquilizer) is Dr. Patrick Bateman. Patrick Bateman is the lead character of "American Psycho". This was most likely an intentional "easter egg" of sorts within the show.
Isaak Sirko: You didn't kill Victor out of vengeance. I have a feeling you're a different kind of animal. The question is...what kind are you, Dexter Morgan?
Dexter: The kind who hunted your friend down and strapped him to a board and put a plastic bag on his head and crushed his skull with a fire extinguisher. The kind who's gonna do the same thing to you, give or take the fire extinguisher.