Factual error: The entire episode is contrived, as the Navy corpsman who is in legal trouble for rendering aid in an accident would not be in trouble due to the "good Samaritan law" in force in Virginia at the time.
Continuity mistake: When the Russian agent is talking to the bad guy, the Russian agent's coat collar changes position in just about every shot.
Visible crew/equipment: When Gibbs and Tony are in Vance's office, after viewing Abby's S-mine video Vance walks over to his desk, and the two green tape marks are visible on the floor where he stands. (00:26:25)
Visible crew/equipment: After Jimmy and Tony's chat, when Tony heads to the elevator Jimmy mutters that he hates being out of the loop. In the next overhead exterior shot of Tony's car, on the rear passenger window we can see the reflection of the boom operator walking and holding the boom pole/microphone. (00:21:30)
Visible crew/equipment: When Tony is with Captain O'Rourke in the parking lot, Borin approaches from behind. As O'Rourke turns to face Borin the actor's microphone has slipped out from under his shirt, between the buttons. Then when Borin says, "So will you," in the next shot facing O'Rourke and Tony, that mic is visible again. (00:38:10)
Continuity mistake: When Gibbs meets with Tom Morrow at the dinner, Tom asks Gibbs if he is going to upgrade to a smart phone. Gibbs opens his phone, the shot changes and his phone is now closed. (00:15:15)
Continuity mistake: In the final scene, Gibbs is working on his boat wearing safety glasses and has a pencil behind his right ear under the frame. When he learns Sergei has survived his pulls his glasses off in disbelief and the pencil is no longer behind his ear. After a cut away to the director and back to Gibbs again, the pencil has returned and remains there for the rest of the scene, including the black and white closing transition.
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.