The Las Vegas massacre on Sunday night was humanity at its worst, yet from its wreckage came moments of humanity at its kindest.

A Los Angeles Fire Department captain named Mark McCurdy came to the Route 91 Harvest Festival with his wife, Kelly Presten McCurdy, and sister-in-law. As bursts of automatic gunfire interrupted the final act of the country music concert and felled the first victims of the deadliest mass shooting in modern American history, McCurdy carried his wounded sister-in-law back to the safety of their hotel room.

Then he turned back to help others with his friend and fellow firefighter, Steve Keys.

Mike Brown, a Las Vegas doctor and former firefighter from New York City, received a mayday call from Kelly McCurdy, his cousin. He drove to the perimeter of the kill zone to collect her friends.

Steve Keys was one of them — he had sustained injuries to his chest as he performed CPR on a fallen concertgoer. He insisted he was fine.

“Wait a minute, you ain’t John Wayne!” Brown said to Keys, though ultimately he was not surprised by the man’s selflessness: “These guys are all firemen. They’re taking care of the people instead of just taking off.”

With bullets striking more and more concertgoers, Kurt Fowler pushed his wife to the ground to shield her from gunfire. A bullet caught his right leg.

Fowler, an EMT and firefighter from Lake Havasu, Arizona, has had surgery and is expected to survive. Several firefighters joined him at his hospital bedside in Las Vegas.

“We are all shocked and saddened from the news,” his captain, Ryan Erickson, said on social media. “He’s one of our brothers.”

Tom McIntosh helped his wife and another woman escape over a fence, but was shot in the leg before he could follow them.

Nearby was James Lawson, who had received EMT training in the Army Reserves. He could see that McIntosh needed immediate medical attention. He took McIntosh’s belt and fashioned a makeshift tourniquet.

Lawson waited with McIntosh for about 15 minutes, until another man pulled up in a pickup truck and offered the pair a ride to the hospital.

McIntosh was reunited with Lawson on live TV on Tuesday.

He credits the stranger with saving his life. “Thanks, buddy. I really appreciate it,” McIntosh said through tears. “I wouldn’t have made it.”

Taylor Winston, a Marine veteran, and his girlfriend, Jenn Lewis, were dancing near the stage when the bullets began to slice the night air. He jumped into an unattended truck and drove more than two dozen critically injured victims to Desert Springs Hospital Medical Center before ambulances arrived on the scene.

“We needed to get them out of there,” said Winston, who joined the Marines at 17 and served two tours in Iraq.

Lindsay Padgett was another survivor, though at the height of the chaos, she was convinced of the worst. “I thought for sure we were all going to die,” she told ABC News. Joined by her fiancé, Mike Jay, she packed five wounded victims and five caregivers into her truck and set off for the hospital.

Jonathan Smith, 30, a father of three, was in Las Vegas to celebrate his brother’s birthday  While herding a group of people toward safety, he was struck in the neck. A GoFundMe initiative to cover his medical costs has already quintupled its $7,000 target.

Dawn-Marie Gray, a paramedic from Oregon, and her husband, Kevin, felt lucky to have won tickets to the music festival through a radio giveaway. When the shooter struck, Gray performed CPR and stanched bleeding victims until first responders could arrive.

Mike McGarry, attending the concert with his children, lay on top of them to try to shield them from danger. “They’re 20. I’m 53. I lived a good life,” McGarry told Reuters. He had shoe prints on his back from people who trampled him to get away.

Todd Blyleven. a former minor league baseball player, his brother-in-law, and a group of volunteers ushered 30-40 people to safety.

“I just felt like I had to,” Blyleven told the Washington Post. “I would hope that if me, or my family, was in a situation like that, that someone would come in and get me.”