In the Dark - S4-E22
Visible crew/equipment: At the start, when Mr. Scott's assistant walks in, the T-mark is visible on the floor in front of the darkroom's door. (00:05:00)
In the Dark - S4-E22
Continuity mistake: Don explains what the investigation is about, and while doing so he has his hands clasped together. Camera changes and they are spread apart. (00:13:20)
In the Dark - S4-E22
Continuity mistake: Don gets a folder out of the bottom draw of his desk, camera changes and he's closing the top drawer. (00:13:15)
In the Dark - S4-E22
Visible crew/equipment: When Don explains how he was about to call NCIS, he leans over to get a folder out. When he does, the camera shadow can be seen moving along the back of his head. (00:13:50)
In the Dark - S4-E22
Audio problem: When Abby is saying how she quit caffeine, the audio in the long shot doesn't match up with her mouth and is a clear overdub. (00:10:40)
In the Dark - S4-E22
Continuity mistake: When Ducky finds agent Lee's bra, he has some sticky labels in his hand in one shot and not in the next. (00:08:15)
In the Dark - S4-E22
Character mistake: On the message board visible in the background when the team is discussing Wong, the word "Artillery" is misspelled "Artillary". (00:18:20)
In the Dark - S4-E22
Revealing mistake: When Tony is telling Gibbs & Ducky that Abby got a hit on the dead sailor's fingerprints, Gibbs takes the file from Tony; the camera shows the file, which appears to be a legitimate profile sheet, but in the comments section, is the script that Tony just read aloud. (00:07:36)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.