Continuity: When Bruce is covering the boy while trains are passing either side of them, at first he has his right hand on top of the boy's head. Then in the next shot he has his hand to the side of his head in a different position. The film cuts back and forth between these shots.

Continuity: When Puzzleline gets the first call from Simon and Leo records what is said, when he is playing it back to the other technician, what is said is different. There are no cutaways, and no editing, but in the playback, Simon doesn't say that he got the number from "Puzzle Nine-Nine."

Continuity: When Jeffries confronts him, Hartley's jacket is partially off. Hartley is pushed back into the van and now his jacket is fully on.

Continuity: When Jeffries and Kubrow are fighting on top of the building the number of parked cars on the street below them changes from shot to shot.

Factual error: A message encrypted with Mercury is shown in the email to the einstein account. The message does not look like it has been produced with a proper encryption algorithm since there are long sequences of letters that are repeated (e.g. GSDX2BYAC52...). A property of all encryption, regardless of algorithm, is by definition that the output be random.

Continuity: When Leo throws the carbon paper away there is a piece of blue and white card standing upright in the bin. When Emily finds the carbon paper it is lying on the same piece of card, which is now lying down.

Audio problem: When we see Emily cycling home we hear the sound effect of a bell but her bike doesn't have one.