A man was shot to death by an armed security guard inside a gas station after a dispute over a barbecue grill turned violent. Surveillance footage shows that a man entered the gas station amd was asked to leave by a contracted security guard, who pushed him back, video shows. The man pulled a pistol with an extended magazine from a holster, which prompted the security guard to "fire in self-defense," police said, using his sidearm to unload more than a dozen rounds. The man, 39, then shot back, police said, wounding the security guard in the thigh, and the guard responded with six more rounds from a shoulder-carried shotgun.