(CNN) Utah State Trooper Ruben Correa headed to a call of a car on the train tracks, but when he got to the scene a man was still in that car -- and a train was coming.

Correa told CNN's Anderson Cooper that he heard the train's horn shortly after he got onto the tracks early Wednesday and found an unconscious man in his 20's at the wheel.

"I was actually trying to unbuckle his seat belt and then I heard a horn. And I looked to my left and I saw lights. And that's when I realized that train is heading straight to us."

Dashcam video from Correa's patrol car recorded his urgent shouts to the driver: "We've got a train coming! We've got a train coming!"

"I had to make a decision at that point," Correa said. "I decide to stay with him and do my best to keep him alive."

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