Like the tens of thousands of others at the concert in Vegas, Melissa Vanderloo and her husband didn’t know what to think when shots started ringing out around them.

“I thought it was firecrackers that went off; and then it went off again,” says Vanderloo. “I turned to my husband and said ‘I think that’s a gun’. Then all of a sudden Jason Aldean stopped playing and everyone started running, and the gun didn’t stop. It sounded like a machine gun.”

Police said at least 58 people died and at least 515 people were injured when a shooter in a Las Vegas hotel rained gunfire down on thousands of music fans at the Route 91 Harvest Festival on Sunday.

It was the deadliest mass shooting in modern U.S. history.

Not knowing where the shots were coming from, Vanderloo thought she was going to die.

“Yeah I did actually,” she says. “We definitely didn’t know what was going to happen. At one point we thought the gunman was right outside the bleachers. It was that close.”

Unharmed by hiding underneath the bleachers, she says all she could think about were her two kids.

“Extremely terrifying,” she said over the phone from Vegas on Monday. “I’m very excited to go home and see my children.”

A group of men from Barrie who were playing cards at the nearby MGM Grand describe the scene as people fled the area.

“People were all running, and it was like a stampede,” said Todd Tuckey from Vegas on Monday.

“It was just the craziest thing you’ve ever seen. They were coming from two different sides of us, and so we decided we better run. We could hear the machine gun firing….we thought ‘this person is coming up behind, in our own building.”

SWAT teams using explosives stormed the gunman's hotel room in the Mandalay Bay Hotel and Casino and found he had killed himself, authorities said. The attacker, Stephen Craig Paddock, a 64-year-old retiree from Mesquite, Nevada, had as many as 10 guns with him, including rifles, they said.

Paul Markle who was with Tuckey says his thoughts are with those affected.  

“There’s going to be a lot of traumatized kids. There was a lot of young people at this concert. The look of terror on their faces…I’ve never seen anything like it,” says Markle.

Both Markle and Tuckey are in are in Vegas for a conference and return home Thursday. Vanderloo returns to Canada Monday evening.