Character mistake: In isolation, Tony mentions John Travolta and says that he's known as the "king of cool." That nickname referred to Steve McQueen, not Travolta. (00:15:10)
Character mistake: When Kate mentions James Bond, and DiNozzo lists the actors who have played him, he forgets Timothy Dalton. As a self-proclaimed film buff, that's not a mistake he would make.
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