Continuity mistake: When Gibbs rejects the agent's file, Cynthia reaches for the ringing telephone with her right hand and Gibbs stops her with his left hand, but in the closeup Gibbs has his right hand on Cynthia's left hand. The closeup is a flipped shot, note their watches. (00:03:05)
Continuity mistake: When Tony tells Ziva he won't help her track down the remaining 'Smiths', a woman in the background is walking down the stairs; as Tony stands up, she takes two steps down from the lower landing. When the camera shot changes on Tony, she's back on the landing. (00:25:15)
Continuity mistake: When Jenny hands the Russian a cigarette the packet goes from green to red. (00:39:50)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.