No one in the group of men outside the Kings Convenience Store on Frankford Avenue Thursday night seemed to notice the man in the medical mask who strode by them.

Until he turned and opened fire with a 9mm handgun.

Surveillance video recovered by police shows how a casual moment outside a convenience store that turned deadly as the still-unidentified gunman killed one man and wounded five others — and sparked a running gun battle that littered the street with nearly 50 bullet casings.

One of the men targeted by the gunman fired back, chasing him down a nearby side street.

Meanwhile, neighbors huddled with their children on their living room floors to avoid stray shots.

The shooting at Frankford Avenue and Allengrove Street Thursday night marked another violent night in Philadelphia as the city’s homicide count climbed to 371. Killings in the city have already surpassed the homicide tally from all of last year, a death toll not seen in more than a decade.

“Every one of these numbers is someone’s family member,” said Philadelphia Police Deputy Commissioner Christine Coulter at the scene Thursday night. “Every one of these numbers represents someone who didn’t come home.”

The gunfire began around 7:45 p.m. Video footage captured the chaos outside the store, as men ran for cover and the gunman fired at a wounded victim on the ground.

That was Ammron Hargrove, 29, whom police found lying unconscious outside the store. He had been shot multiple times, including in the back, and died at Temple University Hospital. A 25-year-old man remains in critical condition — and three other victims are in stable condition, police said.

(Police initially believed seven men had been hit, after another wounded man arrived at the hospital around the time of the shooting. But he had been struck in an unrelated shooting, blocks away, police sources said.)

Police believe the shooting is related to drug sales in the area, which have concentrated outside the store in recent months, and which police have targeted with increased patrols. In the aftermath of the shooting, police found drugs — crack cocaine and marijuana — and drug paraphernalia scattered on the street.

They said one of the men not seriously wounded in the shooting was the gunman’s intended target. But he turned his fire on everyone he could.

On Friday morning, white circles marked the spots on the sidewalk where bullet casings fell.

Business owners said they had grown worried recently about the crowds who had begun hanging outside the store, even through the night.

Maria Rodriguez, who has run a hair salon on the street for 16 years, said she had been afraid that crowds outside the store would eventually bring gunfire. She said three of her regular customers canceled their appointments Friday after learning of the shooting.

“They are afraid,” she said.

One mother on Allengrove Street was home with her young daughter and grandson when the gunfire erupted. She had them lie on the floor for fear that bullets would come through the windows.

Then she had to settle them when they couldn’t fall asleep. In the morning, they asked to go outside to play catch. She told them they couldn’t, anymore.

“I just can’t risk it,” she said.