Someone who has no other options at that point to defend himself
Whatever the reason, it is not the act of a rational man.
Except that was not the case.
Aubery could have trotted right past the truck, ignoring his antagonists commands. He had already done so before. They had no legal method to force him to stop. They did not force him to stop.
Up to the moment when he charged at McMichaels, he was in the clear.
A black man Facing down three thugs chasing him down, coming at him with a shotgun. What else was he to do at that point. In future, people jogging should go armed so the can defend against violent thugs.