When Abby is wandering in front of the "NCIS MOST WANTED" gallery, a few pictures can be seen with red tape across, meaning that they'd been captured or killed. In the bottom row, the seventh picture from the left with no red tape, belongs to "Hasan Mohammed", the character of a terrorist killed in JAG season 8, episode 21 "Meltdown", the Beginning of NCIS.
Several episodes before the garage was on ground floor and autopsy was one floor above, however in this episode ducky says the garage is on the floor above.
In future episodes we learn Abby's lab is on ground floor, autopsy is one floor below so going by that the garage is in basement.
When Ducky is sitting on the morgue floor with his hands on his head, his hands alternate between being on top of his head and not being on top.
The agents do not normally carry their sidearms when in the office, but when Kate takes the evidence to autopsy she has her Sig.
Kate keeps saying that bête noir means nightmare in French. It is actually defined as a person or thing that one particularly dislikes, and literally translates to pet peeve. Nightmare would be cauchemar.
When Kate comes downstairs with the evidence Ari doesn't pick up on the fact her clothes don't match Dr. Mallard's description of Abby as "a goth".
Abby shows concern for Gerald's gun shot before he is shown on the video.
At one point, the intruder tells Ducky that if he doesn't obey a command, the intruder will shoot Gerald's knee. The knee is not a ball-and-socket joint, but a modified hinge joint. With as much as the intruder clearly knows about human anatomy and his being very specific about the kind of joint he would shoot, he should've picked the other shoulder or one of the hips, not the knee.