Mba Kalu was waiting for a customer to pull out her prescription on April 24 so he could refill it, he told WSB.
But it turns out she never had one to begin with.
"I was helping her because she said she wanted a prescription, and I was just waiting for her to pull the prescription out and instead of her prescription, she pulled out a gun. So I just had to react," Kalu, the owner of PCI Pharmacy in DeKalb County, Ga., told WSB.
Police say three women were involved in an attempted robbery at the store and Kalu was able to wrestle a gun away from one of the suspects before they ran away.
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Surveillance video released by the DeKalb Police Department shows three women, each wearing a hat, walk into the store together.
One woman in a black coat approaches the counter and speaks to Kalu while another in red appears to browse some nearby shelves. After a few moments, the woman in red wanders over to the counter, pulls out a handgun and points it at Kalu.
Kalu hardly reacts at all. Then the woman in black pulls out pepper spray and shoots it at his face.
Suddenly Kalu leaps into action. He beats away the woman in the coat's arm, then lunges toward the woman in red, slams her arm to the counter and tries to yank her gun away. Police say the woman had barely gotten the words "Give me ..." out before Kalu grabbed the gun, WXIA reported.
After a few tugs, he wrenches it free and runs to the back of the store as the women are seen quickly fleeing the store on another camera.
"It's either they shoot you or you're going to have to fight them," Kalu told WSB. "I thought, you know, I'm not going to go down like that. At least I have to go down fighting." He told the station his daughter was in the back and he "just had to do what I had to do to protect everybody."
It wasn't the first time he'd been robbed. Patch reported that three men broke in to the same pharmacy with guns and demanded drugs in December.
Police say the suspects drove off in a silver or gray older model vehicle with damage to the right front fender, and that it could possibly be a Ford Taurus or Mercury Sable, CBS 46 reported.