Police were called to a Walmart in northeast Dallas after at least one shot was fired inside the store Monday night.
Dallas police said they arrested Todd Canady, 23, on a charge of evading arrest after he accidentally discharged a gun inside the store in the 9300 block of Forest Lane and then ran from an off-duty officer.
Canady, who has a concealed carry permit, had the .40-caliber semi-automatic gun near his wallet when it discharged.
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A Walmart cashier said she heard a loud boom and then saw a bullet on the floor. She said the man did not appear to be pulling the weapon out or threatening anyone and that she only heard one gunshot.
"It was a pretty crazy experience," she said.
After the gun went off, the man panicked and tried to leave the store, police said. He was quickly apprehended.
Canady sustained a minor injury. Shrapnel from the bullet is believed to have struck two children and their mother, 27-year-old Cassie Schinto.
A Dallas police report said debris struck Schinto in the right ankle, causing pain and swelling. Debris was also believed to have struck her son's cheek and her daughter's shin. None of the injuries were serious and no one required hospitalization.
Tom Massewitz at Targetmaster in Garland said that fleeing the scene violates every ounce of training someone with a concealed handgun license would get.
"You're told, 'Anytime you have to use your weapon, you stay there and explain to the police. Go ahead and unload the weapon, make it safe, so that when police come because they're going to inspect it,'" he said. "That's just part of the conditions of being in a shooting situation."
Dallas police sources told NBC 5 that Canady was carrying a .40 caliber Springfield XD.
The handgun has two safeties -- one on the grip and another on the trigger.
"Both of those have to be depressed for it to be fired," Massewitz said.
Canady also told police he was carrying it in a holster, which gun experts say should have added another layer of safety.
"The primary purpose of a holster -- besides transporting a gun -- is to conceal the trigger," Massewitz said.
Massewitz also said the odds of a gun with two safeties and in a holster accidentally firing were "nearly impossible."
The investigation is ongoing. Officials have not definitively said if they will charge Canady with injury to a child.
Canady is being held on $1,000 bond.
NBC 5's Ellen Goldberg, Frank Heinz and Lindsay Wilcox contributed to this report.