Renner's hero/antihero in "Hurt Locker" could have been an idiot savant. And when it comes to defusing bombs, he's a savant, all right. But he's never an idiot. His supreme confidence imbues him with uncanny alertness. James is the character who embodies what the filmmakers set up as their thesis. For a master warrior like James, the bracing, all-encompassing immediacy of combat, along with its challenge to prowess, can turn war into a drug.