Visible crew/equipment: When Gibbs tells Tony and Ziva to go to Wilkerson's home they pass Abby on their way to the elevator, and just as Ziva waves her hand at Abby, in this shot and a following shot a crew member is visible as he's ducking down by Tony's cubicle, under the monitor on the right side of the screen. (00:04:10)
Continuity mistake: When Gibbs asks Abby to estimate how much time Wilkerson has in the car trunk, just as Abby says, "Depends on the age of the car," this shot is flipped, note Abby's neck tattoo switches sides. (00:10:25)
Continuity mistake: When Tony spots Wilkerson's car in the mall's garage, in the first closeup of the Jetta the trunk has neither the Jetta badge nor the VW emblem, but in following shots both the Jetta badge and VW emblem are attached to the trunk. (00:14:55 - 00:16:55)
Continuity mistake: When Tony and Abby determine where the car holding Lt. Cmdr Wilkerson hit a pair of railroad tracks, Tony has a napkin tucked into his shirt like a bib. In the next shot, the napkin has disappeared from his shirt, and he is holding it in his hand instead. (00:25:10)
Visible crew/equipment: During the scenes in Lafferty's house, crew/camera movements are reflected on the large glass fish tank near the front door. (00:27:40 - 00:35:00)
Answer: I hadn't seen the backdoor pilots yet but while it wasn't explicitly stated, at least onscreen, I heard somewhere Vivian got either fired from NCIS due to jeopardizing a case, got resigned from the agency, or transferred to the FBI.
Raykvega423