There is a resounding crack as Caleb Harrison hits Reid directly in the mouth with the barrel of his gun, and—though Reid has been hit in the mouth more than is probably proportionate to his age—it hurts like a bastard. But it means that Morgan can hold his gun on Harrison and bark out the familiar order—hands up, weapon down—and that the gun falls to the dirt. Reid backs up, letting Morgan force Harrison's hands behind his back, chivvying him into the back of the waiting police car. Reid's job was done: he was supposed to goad Harrison into drawing his weapon, though he was quite sure that he wasn't supposed to be hit with it.
"You okay?" Rossi asks, and Reid nods, reaching up to touch his lip; his fingertips come away wet and sticky with blood. "Sorry about that... you weren't supposed to get hit, I don't think," the older agent adds.
"Yeah, I'm fine," he says quietly, automatically, and Rossi nods, turning towards Morgan and the unsub. Reid pauses for a moment, probing a loose tooth with his tongue, and spits a mouthful of blood on the ground, saying, after a moment, "Fuck."