By Leinz Vales, CNN

(CNN) -- When a gunman started firing into a crowd of concertgoers in Las Vegas on Sunday night, Iraq war veteran Taylor Winston thought on his feet.

Bullets were flying. People were injured. Winston saw a truck with the keys still inside in a lot near the venue, and didn't hesitate to jump into action, he told CNN's Anderson Cooper Tuesday.

"Once we were in it, we decided to go help get everyone out of there," he said. "Shots were still firing, we had a couple of friends ... set up a make shift hospital on the backside away from the gunfire, and they were pulling people out of the venue. We pulled up to that and they started loading us up with the most critical injured."

By the end of the night, at least 58 people were killed and more than 500 were injured, making it the deadliest mass shooting in modern US history.

"It was still quite scary, but we just knew they had to get to the hospital immediately," Winston said. "No ambulances were immediately available. There was far too many causalities for anyone to handle. Probably one of the hardest parts was leaving everyone behind that I couldn't fit in who were still critical injured."

Winston recounted making two trips from the festival grounds to the hospital.

"We took them first round and dropped them off," he said. "We had help at the hospital to get them all out and get them into the hospital and once we were clear we just said 'let's go back for me.' We went back for a second trip and filled it to the brim of essentially bodies, some barely breathing, and had people applying pressure and trying to help them survive to make it to the hospital."

Cooper asked Winston about how his military training helped him through such a horrific ordeal.

"I think a lot of my training helped in the event, helped me keep a cool head," Winston said. "But at the end of the day, we just knew we had a mission to get as many people to safety."

The-CNN-Wire

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