Other mistake: Derek sees the Cadillac circle the block after he walks Danny to school. He looks at the car and knows something is wrong. So he runs back to the school and in that short amount of time the crime scene is roped off and cops are everywhere.
American History X (1998)
1 other mistake - chronological order
Directed by: Tony Kaye
Starring: Edward Norton, Edward Furlong, Ethan Suplee, Elliott Gould, Beverly D'Angelo, Fairuza Balk, Avery Brooks, Jennifer Lien
Continuity mistake: Toward the beginning, when the principal calls Danny into his office to discuss his Mein Kampf paper, he first glares at the Jewish teacher who exits the principal's office. As the teacher is walking past, the clock on the wall reads 8:10. But when the camera angle changes to show him walk around a corner, the same clock reads 8:20. Apparently it took him 10 minutes to turn the corner.
Murray: He's lost.
Trivia: At the end, when Danny is heard quoting from the paper he wrote for Dr. Sweeney, the quote which begins "We are not enemies, but friends..." is the closing paragraph from President Abraham Lincoln's first Inaugural Address on the 4th of March 1861.
Answer: The tattooed DOC on gang members' arms means Disciples of Christ - the gang that they belong to in the movie.