Visible crew/equipment: While Ellie and Nick are undercover they meet Donnie, and when Ellie walks behind the store's counter the yellow T-mark is visible on the floor. (00:16:30)
Revealing mistake: Right at the start, in the tight closeup just as Sweeney squeezes the trigger, "Replica Independent Studio Services Sunland, CA" can be seen engraved on the prop weapon. ISS is a supplier of props for production studios. (00:00:10)
Continuity mistake: They say the suspect was dishonorably discharged in 2008. A minute later in the episode they say he was dishonorably discharged in 2010. (00:10:50 - 00:11:55)
Chosen answer: "Policing your brass", means to pick up your expended shell casings, after firing your rifle, or pistol.
pross79