The spelling of two character names changes between Parts I and II. In Part I, Ken Briscoe spells out a name as Helen Katish, K-A-T-I-S-H, reading the name from his written record. (Actress Nahanni Johnstone is listed only in the opening credits.) But in Part II's subtitles and the end credits, the name changes to Katisch with a "c" added. Also in Part I's end credits, Amy Hohn is listed as Delea. But in Part II's end credits she's Delia Woodruff.
Detective Munch describes a Black Talon bullet as a "cop killer." Actual "Cop Killer" bullets are armor-piercing rounds, designed to penetrate police officers' body armor. Black Talons are hollow-points, which sacrifice penetration, in order to inflict greater soft tissue damage.
Munch says that Black Talons "haven't been made since 1994" In actuality, they were removed from public sale in 1993, and production ceased in 2000.
At the very end of the episode, as the credits appear, Captain Cragen is walking away from Sergeant Munch. You can see that the direction Cragen is walking ends in a dead end consisting of a U-shaped bench, meaning there would be no where for him to go. Presumably had the scene continued Cragen would have run into the bench.
When the squad is talking about the suspect's description ("Buddy Holly glasses" etc.) and his M.O. of shooting couples in their cars, Capt. Cragen recalls an old case that Detectives Briscoe and Logan investigated years before when he was head of the 27th Precinct homicide division. The case he refers to is Mayhem (1994), which took place after Cragen had left that department and Lt. Van Buren had taken over . So, when he calls Lennie Briscoe and asks about that case that "we" had, he should have said, "you."