Retired teacher and avid hunter Mike Cronk knew instantly the staccato sounds coming from the Mandalay Bay Resort and Casino last night were the real thing.
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"I heard some of the bullets hit the fence, and it's aluminum," Cronk, 48, told ABC News' Matt Gutman. "That's how we knew these weren't firecrackers."
Thousands of country music aficionados who were enjoying Jason Aldean's set at the Route 91 Harvest Festival outside Mandalay Bay were instantly transported into a war zone.
The suspected gunman, identified as 64-year-old Stephen Paddock, sprayed the makeshift concert grounds with gunfire from the 32nd floor of the luxury hotel, killing at least 50 and wounding more than 400. Authorities said Paddock killed himself.
As the shots erupted, Cronk said he saw his best friend, 52-year-old Rob Macintosh, get hit.
"My buddy, after some of the popping, was like, 'I got hit!' and my buddy got shot three times," Cronk said.
"I saw him there and I wasn't going to leave him," Cronk said.
Cronk said EMTs and ex-military members hunkered down to help his friend and other victims stay alive.
"We probably stayed there like for at least 10 minutes before we made a decision to get him over the fence and under the stage so at least we knew we were safe dealing with him," Cronk recalled.
Cronk and others moved Rob behind the concert stage to take cover from the bullets. At that point, Cronk started to staunch his friend's bullet wounds under the direction of a woman who was with them.
"We kept [Rob] compressed," Cronk said. "[Rob] actually put his finger in the [bullet] hole."
Stabilizing Rob as best he could, he and four other people tending to the wounded attempted to get to a hospital by hopping into the bed of a pickup truck.
Cronk was beside himself with emotion as he described helping a badly injured man into a ambulance. The man ended up dying in Cronk's arms.
Cronk said he then received a call from Rob's daughter.
"She told me, 'Dad talked to us and he's going to be OK,'" Cronk said. "That took a load off me."
The bullets that struck Rob were only inches from Cronk.
"It could have been me that got shot," he said through tears. "So many people ... very thankful right now."