Toward the end, when they're all rushing toward the building with the sniper in it, if you go through in slow motion, you can see someone pass in front of the camera.

R. Lee Ermey was outstanding as the DI, although since he was a U.S. Marine for 11 years, IMHO he did little more than play himself. (He also made Lou Gossett's Sgt. Foley from An Officer And A Gentleman look like a pussycat.)

FYI, he played virtually the same role in 1979's "The Boys in Company C". I knew he was authentic, having graduated from Boot Camp shortly before that.