Factual error: When Queenan and Costigan are riding the Red Line, Queenan gets on at Park Street station. Costigan tells him, "Get off at the next stop, South Station." South Station is two stops away; the next stop after Park Street is Downtown Crossing. However, Queenan does get off at the next stop, and it is magically South Station.
Visible crew/equipment: When Queenan dies after being thrown out of the building and his body is crushed on the ground in front of Costigan, as he looks at his hand covered in blood, in the shot on the top on the left side of the screen the dolly track of the camera is visible for a second.
Continuity mistake: When Frank asks for "numbers", Madolyn is moving into the apartment. In the next scene, when Costigan and Madolyn "get together" she is shown as moving out, but it seems that Costigan was giving his numbers then leaving the hideout to go get with Madolyn.
Continuity mistake: At the end of the scene where Costello smashes Billy's hand, he pulls out a wad of cash with his left hand, peels three bills off with his right hand and throws it on the table, saying "Get your hand taken care of," then in the next shot, has the wad in his right hand and throws that down on the table, and the three bills he just dropped are no longer on the table.
Factual error: When Costigan takes the Dr. Smith-prescribed Oxycontin tablets, the tablets are incorrectly shown as large, white oblong pills with the prescription bottle just labeled 'Oxycontin'. In reality oxycontin tablets are small, round, various colored pills (dependent on mg dose) with the dosage number (in mg) imprinted on one side of the tablet as 10, 15, 20, 30, 40, 60, 80, and 160 (I believe 160 mg tabs are discontinued) and the opposite side imprinted as OC or OP. Also, the dose (in mg) would have been printed on the front bottle label.Bluehairdriver
Factual error: When the MSP close in on Costello in Sheffield, they come in silently but still have their parking lights on. Pretty useless if you're "sneaking up" to a drug bust. Secondly, patrol officers don't have automatic weapons, as shown in the shootout.
Continuity mistake: When Sullivan is checking the CCTV recording, we can see the "citizens" envelope, lying on his coat, on a desk or a chair. First, the folded part of the envelope with "citizens" written on it is upright, with the word appearing upside-down. Then, as he grabs his stuff to leave, the position of the envelope has changed to horizontal. (01:30:00)