(at around 30 mins) During an establishing shot of Dr. Mallard's home when DiNozzo arrives to watch Mrs. Mallard a large lighting fixture can be seen on the upper balcony with a diffusion screen attached in front.
In one scene, the mother of a murder suspect tells Gibbs that her son couldn't be a killer because he went to medical school. Gibbs quickly replies that Jack the Ripper went to medical school too. No one knows the identity of Jack the Ripper, a popular theory is that he was a surgeon or physician, but butcher and slaughterers have also been suggested, due to the assumption that he had knowledge of anatomy. So no one knows if he actually had medical training.