Character mistake: Morgan asks Reid what track on the CD (Some Kind of Monster by Metallica) would help an insomniac sleep. Reid replies with "Enter Sandman" however, Some Kind of Monster doesn't feature the song Enter Sandman. (00:29:00)
Other mistake: At the start, it's nighttime when the unsub hides in the house of the soon-to-be victim who goes to sleep when her alarm clock reads 'Tue 11:06', and then we see the time morph to 'Tue 1:13' when the victim is sound asleep, before the unsub comes out of the closet to kill her. However, the time on the clock should actually read 'Wed 1:13'.
Agent Hotchner: This is Special Agent Dr. Reid.
Man: You look too young to have gone to medical school.
Agent Reid: They are PhD's. Three of them.
Man: What, are you a genius or something?
Agent Reid: I don't believe that intelligence can be accurately quantified, but I do have an IQ of 187, an eidetic memory, can read 20,000 words per minute...yes, I'm a genius.