The 26-year-old man who is credited with disarming the California shooting suspect had never actually held a firearm in his hands.
Brandon Tsay was working late on a Saturday night at his family's dance hall in Alhambra when he found himself staring at one that was pointed right at him.
According to Mr. Tsay, "my heart sank; I knew I was going to die.". .
He did not know the gunman was believed to have killed 10 people just minutes earlier at another dance hall.
A further tragedy was avoided when Mr. Tsay lunged at the man and eventually disarmed him.
Huu Can Tran, the shooter, was found later to have committed suicide in a van after suffering a self-inflicted gunshot wound.
The mass shooting was one of the deadliest in Californian history. At the well-known Star Ballroom Dance Studio in Monterey Park, about seven miles (11 km) east of central Los Angeles, it started at approximately 22:22 local time on Saturday (06:22 GMT on Sunday).
Celebrations for Lunar New Year had been under way in the area, known for its large Asian population.
The shooter was confronted by Mr. Tsay at the Lai Lai Ballroom and Studio in the neighboring town of Alhambra about 30 minutes after the shooting.
He saw the shooter's semi-automatic assault rifle pointed at him while he was in the office next to the lobby.
Computer programmer Mr. Tsay told ABC's Good Morning America that he did not recognize the man.
Mr. Tsay observed that the man appeared to be searching for targets or potential victims.
Mr. Tsay claimed that when the shooter began preparing his weapon, "something came over him" and he realized he needed to "disarm him otherwise everyone would have died.".
"When I got the courage, I lunged at him with both my hands," he said.
Mr Tsay said the man left and jogged to his van after he finally wrestled the weapon away and yelled, "Go, get the hell out of here!" for a brief period of time.
"Immediately I called police with the gun still in my hand," he added.
Initially, Sheriff Robert Luna of Los Angeles County said it had been two people who wrestled the gun away, but CCTV shows only one person - Mr Tsay.
The Lai Lai Ballroom