I don't feel like I would fire a warning shot if I wasn't fearful, but that's just me.
I do agree he would have been golden if he'd have shot him the first time--not sure if we'll ever find out if it was a warning shot or a negligent discharge.
I'm hoping there is more video so we can see if CR was advancing toward KC before the final 2 shots. There is a still photo floating around that makes it appear he was, but I think video is needed to confirm the timing of the shot and the lifting of his leg that makes it appear CR was moving towards KC. As Andrew Branca said in the video posted up thread, even a shift of CR's body weight toward KC would make it more likely to be self defense.