The couple had arrived with a group and were there for an evening of fun, music and good company.
But as country music star Jason Aldean performed, gunfire erupted and a deadly rain of bullets began falling on the crowd. Frost, 27, was among the almost 500 who were injured in the carnage -- a bullet striking her above the right eye.
Boyfriend Austin Hughes was unhurt and, with help from a stranger, carried Frost to a nearby truck. Hughes held his shirt to Frost's wound until they arrived at a hospital.
Fifty-eight people lost their lives as gunman Stephen Paddock fired round after round into the panic-stricken mass of people. Somehow, Frost survived. The story of her survival is about beating the odds, her father said.
"I was told 90% of those shot, as she was, die," Rich Frost told the Las Vegas Review-Journal.
"Well, it looks like she's in the 10% ... slowly but surely she's making progress."
'She's a fighter'
There has been an extraordinary outpouring of support for the wounded woman and her family since the October 1 massacre. More than $512,000 in donations had been made by Thursday afternoon to help cover medical and other costs. But the display of love and unity has not relieved the heartbreak felt by Frost's mother, Mary Moreland.
"I'd throw it all away to have my daughter back," said Moreland, her voice breaking with emotion. "It's overwhelming."
The removal of the bullet also meant removing Frost's right eye, according to details posted on the family's GoFundMe
page. And to allow her brain to swell, a bone from her forehead was removed. It will be replaced in a few months. But the bullet that shattered Frost's life will always be with her.
"She'll have pieces of the bullet in her brain forever," Moreland said. Reconstructive surgery will be necessary to repair Frost's face and eyes.
With that long process in mind, Frost's neurosurgeon, Keith Blum, contacted biotechnology company KLS Martin Group. The company has agreed to donate surgical implants that will be needed to repair her face, according to the Las Vegas Review-Journal
Maryland native Frost is still being evaluated for brain damage. While she has already shown some improvement, her recovery is expected to be a long, uphill battle. She is in critical but stable condition, her father said via Facebook Messenger on Thursday.
Given the extent of her injuries, Moreland said she is grateful her daughter is alive. "It's very hard. When I first saw her, it was all I could do to keep composed, but she's a fighter and it doesn't matter what she looks like -- it matters in here," said Moreland, gesturing to her heart.