Matthew Russo was on a Las Vegas tour bus when he and the other tourists were instructed to take cover immediately, on Monday, Oct. 2, 2017.

A gunman shot and killed at least 50 people and wounded another 400 from his hotel room at the Mandalay Bay Resort and Casino on the Las Vegas Strip.

The gunman, later identified as Stephen Paddock, shot into an estimated 22,000-person crowd gathered for a country music concert. Paddock opened fire and chaos erupted as thousands fled for cover.

Russo said someone instructed everyone to get off the bus and get down as the bus passed the concert venue.

People were running in droves away from the concert grounds.

"They put us in a hotel and wouldn't let us leave," Russo said they were on lockdown for at least four hours.

Russo said he and his family members met another person locked in the hotel whose husband had been shot.

"It didn't sound like anything I've ever heard before. I've never heard gunshots ring out like that. They were just going nonstop. I would've never guessed it was gunshots," Russo said.

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