Some of the attendees at Sunday night's Route 91 Harvest Festival in Las Vegas were from New England, including one woman from Methuen, Massachusetts, who described the scene as "chaotic."
Mandi Thornton said it was "pure panic and chaos." And to make matters even more confusing, she had no idea who was shooting.
"I just feel really numb right now. Not really sure what to think about it," she said.
The mass shooting during the concert killed at least 59 people and left more than 500 injured. The suspected gunman, Stephen Craig Paddock, is believed to have killed himself before SWAT agents entered the room in the Mandalay Bay Resort and Casino from where he was shooting.
Thornton and her friend were standing only five rows away from the concert stage when she heard the first wave of gunfire.
"It started happening again, you could hear the bullets ricocheting off the stage," Thornton recalled.
Thornton spoke to NBC Boston from her Las Vegas hotel room on Monday morning via Facetime.
"I honestly was thinking, 'I need to run, like I'm going to die if I don’t get out of here,'" Thornton said.
She described the scene as pure horror once people realized that someone was shooting.
"To us, we didn’t know if this person was in the crowd or if it was someone chasing people around. We had no idea," she said.
Thornton said she and her friend managed to escape unharmed and took cover in a nearby hotel bathroom.
"We were next to this kid who had been shot. He said he was OK, but he had been hit in the rib - he was bleeding," she said.
Thornton said she is still struggling to process the aftermath.
"There had been all these other people with wounds from falling or being trampled," she said.
Thornton said they were four songs into the Jason Aldean concert across the street from the Mandalay Bay Hotel and Casino when an evening of fun turned into a massacre.
"Something like this happens, you know. It never makes you want to do something like that again," Thornton said.
Immediately after Thorton fled, she said she called her parents back home in Methuen who had no idea what happened until they received a voice mail message.
"She wanted me to know she was OK," said mom, Cheryl Jabour.
The fact that their daughter could have been killed is now starting to sink in.
"I feel bad for all those other people who may have lost their kids," said Jabour.