He started firing when the guy was facing him. Even after he turned, he was still armed and still very close. IMO, that still constitutes a threat. After all, he hit him with a 32 so it couldn't be all that far away. :)
I don't see turning alone as a stop sign for defending yourself. It seems to me I have seen a number of cases in Texas as least where people were not raked over the coals for shooting someone after they turned. There might be different case law in your state though.
I guess I really, really dislike the notion that just because someone turns around real quick that justified lethal force automatically becomes murder. It is good for the shooter to keep in mind, but sucks as a legal precedent.