Agent Dunham retrieves a small frame Glock 26 from her ankle-holster at the warehouse and hands it to Peter, stating "the safety is on the right." Glocks have no external safeties.
Dr Penrose's computer record shows his first name as Claus but on the second line the name is spelt Clause.
When discussing why the killer removes the pituitary gland, Peter incorrectly states the pituitary gland is the "boss" of hormones of growth and aging. While the pituitary gland is a critical site of production and storage of hormones, it is the hypothalamus as well as negative or positive feedback loops from other glands that regulate the distribution of hormones.
Several mistakes when Peter tries to revive the girl at the warehouse near the end of the episode: Firstly, defibrillators are not used to restart a heart during asystole (the time in which the heart doesn't beat at all - flat-line on the monitor), instead, CPR (cardio-pulmonary resuscitation) is the correct method. Defibrilator discharges are used during fibrillation to stop chaotic an ineffective heartbeats ("fibrillation"). Secondly - Peter uses some metallic objects to conduct the electricity, however he places them over the drapes covering the girl's body. To prevent burns and other injuries, conductive gel is placed between the metallic plate of the defibrillator and the skin of the patient, certainly not a paper drape. Thirdly, Peter simply takes too long to build his makeshift defibrillator for the resuscitation to be effective.
Near the beginning of this episode, Olivia is shown, at home, reviewing open case files involving Special Agent John Scott. These file are marked SECRET. It is illegal to remove classified files from a secure facility so she shouldn't have these files at home.
Grammar: Olivia Dunham says to Broyles "Hey, I got here as fast as we could".
I, singular, as in herself but then uses "we", plural.
Since she arrived with Walter and Peter, correct grammar should have been: "We came here as fast as we could"
When responding to Olivia's description of the serial killer's pattern, Peter's audio is slightly out of sync with his lips and the audio quality of his voice has a different acoustic quality than Olivia's.
Stoughton, Massachusetts is completely landlocked and as such has no bridges. It is also several miles away from Sudbury, Massachusetts.
When Walter and Olivia are going through the files they find a connection to a Dr. Penrose. Olivia motions for Farnsworth to run a check on him. Farnsworth types in a search for "Dr. Claus Penrose". Neither Olivia or Walter had mentioned his first name though.
While attempting to lull himself to sleep at the end of the episode, Walter recites a sequence of numbers which is known as the Fibonacci series, where each number in the sequence is equal to the sum of the two preceding numbers: 0, 1, 1, 2, 3, 5, 8,13, 21, 34, 55, etc. The problem is, he skips 5.
Astrid mispronounces Dighton "Ditton." It is correctly pronounced "Die-ton."