Revealing mistake: Whenever James, Sanborn, and Eldridge are riding in the Humvee, you can see panels of wood in between the doors and windows of the Humvee. If you look closely, the grain in the wood is visible.
Visible crew/equipment: When James is walking in his EOD suit, a crew member and camera can be seen in the reflection of the top of his helmet. (02:05:30)
Factual error: Sgt. James (Renner) is with a 5th Generation iPod Classic in his room at Camp Victory. This iPod model wasn't released until 2005 while the film is set in 2004. In addition, he is wearing 2007-era Apple headphones, which weren't available in 2004 either.
Answer: It's a term similar to "a world of hurt". It's both outside of you and within you. The outside definition is that a hurt locker is anywhere you go to find pain. In the film's case, war-torn Iraq is the hurt locker. Inside, your hurt locker is the place you bury your anguish.
johnrosa