Wild Justice is probably the closest thing to convincing me that Bodie could do serious mayhem if he wanted to - but even then, when it came down to it, he didn't. He watched King Billy in the pub, and presumably had tracked him down, but the worst he did was take his anger out on his car door. Then he tracked him to the motorbike trials, but he took Doyle with him then. It was Doyle getting mad with him and leaving that meant Bodie was on his own, not Bodie's choice to go after King Billy alone - "with a little help from my friends", he assumed, until Doyle disabused him of that idea.

Then in the fight in the woods, it's what S2k said above about things being in the heat of the moment - Bodie's fighting for his life because he's outnumbered. Would he have broken King Billy's neck? I'm not convinced that he wouldn't have flipped him around somehow and just had him out cold if Cowley hadn't shown up just then.

And even before all that, he when to Shusai to work out what to do. Shusai gave him the metaphor of just destroying something with sudden violence, but Bodie didn't actually do that, either. Maybe he thought he could - but he didn't ever try to get King Billy on his own and just kill him in his sleep or something, which would have been much simpler (given SAS skills) than what he actually did do...

So I dunno - I'm still not seeing anything that makes me believe he's the kind of person who'd kill a surrendered man, or coldly beat people to death in holding cells...