An Alberta man and his girlfriend are safe after making a last-minute decision to leave a Las Vegas concert minutes before a mass shooting killed more than 50 people and injured hundreds, including the friends they were standing with.

On Sunday night, Steve Chwyl was watching country star Jake Owen perform at the Route 91 Harvest Music Festival with his girlfriend, Lauren Guhl. They decided to leave at 9:40 p.m., about 10 minutes before Jason Aldean took the stage.

They had seen him perform in August at Big Valley Jamboree in Camrose so they decided to call it an early night and beat traffic back to their nearby hotel.

"We were just walking out as he was playing," said Chwyl, who is originally from Beaumont but lives in Calgary. The couple listened to Aldean as their taxi drove away.

At around 5 a.m. Monday, the phone rang in their room. It was one of their friends, asking if they were OK. 

'Waking up to this has been a little shocking'

As Jason Aldean performed in an outdoor venue in an area known as Las Vegas Village, a gunman perched on the 32nd floor of a nearby casino fired a hail of bullets into the crowd below as thousands of concert attendees ducked and ran for their lives. At least 50 people were killed and over 500 people were sent to hospital. 

It's the deadliest mass shooting in modern U.S. history.

Authorities identified the gunman in Sunday night's shooting as Stephen Paddock, 64. It's believed he killed himself before police reached him in a hotel room. 

"Waking up to this has been a little shocking to say the least. We looked at our cellphones and that's when we realized something bad had happened," Chwyl said.

"We started reading through our messages then we turned on the TV to see the news everywhere, that shots rang out at Jason Aldean, right after Jake Owen had played."

'It's terrifying when you think we were literally standing right next to the people that were shot.' - Steve Chwyl

Chwyl said he immediately checked in with some friends from California they had met days earlier. They'd all been standing together at the concert Sunday night, at stage left near the sound booth.

"One of them was shot in the femur. He's critical, but stable, as far as we know," Chwyl said. "One was grazed [by a bullet], and the other one was shot in the arm."

Chwyl said he's grateful he and his girlfriend weren't caught in the attack.

"Little shaken up I guess. Divine intervention. It's terrifying when you think we were literally standing right next to the people that were shot," he said.

The couple is returning home to Calgary this afternoon. They've spent the morning in their hotel room and talking to friends and family. 

"We're OK," he said. "We can't wait to get back to Canada."

Harvest festival

Chwyl took this photo at the Las Vegas music festival Sunday night, minutes before the mass shooting broke out. (Supplied/Steve Chwyl)