I've watched the video several times, and he didn't even gas it until he was next to guy. To me it appears that he was almost past him, or at least mid car when he hit the gas. Maybe to get away? Not that it mattered, but it didn't look like he gassed it before him causing any kind of slide.

Can't really say that hasn't been already stated. The guy was an idiot for getting out of his car when there was no need. Now if his car was on fire I can totally understand it. But he was just pissed and a moron that picked the wrong way of dealing with it.