DALLAS -- In the minutes when police say Stephen Paddock opened fire, people’s lives were up to fate. Proof of that arrived on the early morning flights from Las Vegas to North Texas, where we learned simple decisions may have saved concertgoers lives, like Fred Pertivelli’s.

"We were at the show all weekend and then we decided we didn’t want to see the last act, so we ended up leaving probably half an hour before it all started," he said.

Others' lives are permanently changed. Amy Santos of Plano is one of them.

"I have no words, I’m just stunned," she told us after arriving at Dallas Love Field Airport Monday.

She was in Vegas with her friend Diana George of McKinney. They were walking toward Mandalay Bay to meet up with friends around 10 p.m. Sunday night.

"We heard the music, to an extent, as we walked to the Mandalay Bay," said George. "But then the music just stopped, and that’s when we heard the rapid gunfire, and it was lengthy."

Santos grabbed her phone and started rolling. In it, you can see people running from the Route 91 Harvest Festival, and then hear 10 seconds of gunfire.

"We just heard what sounded like firecrackers but immediately, I just told Diana, 'That sounds like an AK-47 or an automatic weapon," said Santos.

They joined the thousands running for cover.

"We hid in the stairwell of the MGM Grand for a while, until we felt we could climb up to where our room was," said George. "Then we got into our room and they put the hotel on lockdown."

What followed was a sleepless night, that made the weekend’s fun memories feel like another life.

"We were just at a J. Lo concert on Friday night and we were just saying, that could have been us!" said Santos.

Now back home in North Texas, they ask themselves if anywhere is truly safe.