When Gibbs is in interrogation, he moves two pictures depicting US Marines with his hands, so that the pictures are above the image of the deceased Marine - Michael Torres. Subsequently, the camera focuses on Capitain Joe Westcott, and then turns back to Gibbs. At this time, the two pictures of the Marines are not above the other one, but rather on the other side of Gibbs' folder.
In the beginning when the NCIS team is at the scene of the crime underneath the elevated electric train rails, a train horn can be heard as the elevated electric train passes over head. Elevated trains don't need to blast their air horn (even if they have one) to warm people off of the tracks because they are elevated with no cross traffic, there would be no reason to blow the horn.