It was the last place that a US Army Veteran expected to find the type of chaos and heartache he saw during the Iraq War.

But late Sunday night, Chris Bethel found himself only two floors below the gunman perched high in a Mandalay Bay hotel room.

"Police told me later he was on 32nd floor, room 135. I was on 30th floor, room 128," said Bethel. "I remember, he switched weapons. The caliber sound switched. He went from automatic to sniper rifle. Phew, phew, just a totally different sound."

Bethel, who lives in Haltom City, says he tried desperately to contact Vegas police and hotel security after the initial shots were fired.

"The rounds are not stopping. Seconds are going by when I make the phone calls, and the rounds are still going," he said.

He was eventually able to get through to hotel security and police. It wasn't long before officers were swarming his floor on their way to the shooter's room two floors higher.

"They locked the hotel down for a long time. SWAT came through each room in the middle of the night," said Bethel.

The Army veteran says he wishes he could've done more to help stop the carnage. He turned out the lights in his room, even monitored the hallway, because it felt and sounded like the shooter was even closer.

"You relive the night over, and over, and it tears you up," he said. "I'm traumatized."

Originally in town for an IT conference, Bethel said he caught one of the first flights he could Monday to return home and see his family in North Texas.

"Everyone wanted to get out."