[He kind of jumped at the smack to the back of the head, and looked like a startled dog for a moment.]

[Man, when WAS the last time someone did that to him?]

[... no really, honestly, it surprised him.]

[He rubbed the back of his head, scowl starting to sink in now. Hey, that was uncalled for.]

I know, I know... ya can't keep all promises, but this one aint the same as protectin' her. I can't... protect her. [his promise is worse, he thinks. His was he'd kill her again if she started to hurt anyone. If it meant the destruction of everything.] I just gotta make sure she's... not out there.

[note: he might have taken a step back from Marco, in case he tried that smack thing again]