Visible crew/equipment: On the rooftop, after Caitlin leaps in front of Gibbs and takes the bullet in her vest, just as Gibbs and Tony help Caitlin stand up, in this shot the blue crash mat is visible on the ground. (00:41:45)
Revealing mistake: When Kate is shot by Ari, Michael Weatherly flinches before the sound of the gunshot, in anticipation of the forthcoming squib explosion. (00:42:20)
Chosen answer: "Policing your brass", means to pick up your expended shell casings, after firing your rifle, or pistol.
pross79