A few thoughts:  If Darryl Freeman had a gun immediately at his disposal in his van and saw this outraged guy coming at him with intent to possibly harm him, wouldn't showing the weapon in advance be a deterrent to Pahio from trying to beat up Freeman?  Unless Freeman waited for the right opportunity to really finish the job.  Also, if Freeman did not intend to kill, wouldn't he have aimed at a less vulnerable part of Pahio's body in order to only disable and not kill Pahio?  Finally, running over someone who he just shot tells me that there was no remorse for what he just did, but rather a reaffirmation that he really wanted to kill Pahio.  The initial shooting may have been in self defense, but driving over the victim's body tells me that it was cold hearted murder.