reckless endangerment?

So, yesterday, a man robbed the Verizon store on White Bridge road (and today, appears to have committed suicide). From yesterday’s story on the robbery:

Authorities said the man held up five store employees and two customers inside, and when he came out into the parking lot, he held up a third customer.

He didn’t realize that customer also had a gun. Police said the customer pulled a handgun and fired several shots at the robber.

A News 2 crew on the scene said four shots were fired in the parking lot as the suspect was fleeing.

No one was struck.

The customer missed his attacker but possibly hit the getaway car, 2005 or 2006 silver Ford Escape SUV.

Investigators said the victim did have a handgun carry permit and according to police, was within his rights to pull his gun in self defense.

Can anyone familiar with the law explain this to me? Is it state-specific? How is discharging a weapon in city limits at a person that is fleeing (i.e. not constituting a threat to the shooter, or anyone else) not reckless endangerment or something? I was under the impression that in most scenarios, shooting at someone that presents no immediate threat was illegal. That issue aside, his choice strikes me as wantonly irresponsible – that area is extraordinarily crowded. He could have hit any number of innocent bystanders.

WKRN’s article seems to be framing this debate in the context of carry permits and where it’s legal to have a firearm:

Where it’s appropriate to have a gun has been a hot topic for lawmakers in recent weeks.

The legislature recently approved a bill that will allow handguns in restaurants that serve alcohol, as long as the person has a carry permit.

Mitch Shelton does not support the legislation.

“You’re at a family restaurant… No guns should be allowed in a place like that, no way, shape or form,” he told News 2.

When it comes to self-defense, Giles said it’s a different issue.

“That’s a horse of a different color. When it’s defense, that’s a different story,” he said. “You pick and choose where you go. Hopefully it’s a safe place.”

This seems to me to be missing the point entirely. This has nothing to do with whether or not he should have had a gun. It has everything to do with whether or not he should have discharged it – and it shocks me that his actions are being considered “within his rights”. What am I missing?