Visible crew/equipment: When Gibbs tells the team to gear up because there's some kind of gas leak at Quantico, at the start of the first shot at the high school, the blue tape mark is visible on the floor between McGee's feet. (00:03:05)
Visible crew/equipment: While Gibbs and Ziva are interviewing the teacher in the classroom at Quantico, in the wide shot facing Ziva as she confirms the number of students, there are two red tape marks on the floor beside the two back legs of her chair. (00:05:20)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.