The microscope used by David and then DB to look at the slide of Becca's lip tissue is only a monocular (one eye) microscope. This would not be used in the best CSI lab in the country. They would be using binocular (using two eyes) microscopes. Also noted, David did not use oil on the slide, which is something used in order to "read" a slide. (I'm a retired medical technologist, and microscopes were primary tools I used every day.)
David Phillips graduated high school in 1998 according to this episode, yet two years later in the Season 1 Nov 2000 episode Friends & Lovers he is already working as Assistant Medical Examiner.
When explaining how his former classmate killed herself, David says she hung herself. As assistant medical examiner, he should know the correct word is hanged. (All the CSI's should know this also, and no one corrects him.)