Bondi Beach heroes show why everyday people run toward danger

But footage from the scene showed there were other instances of heroism that day: A retired mechanic rushed one of the attackers and grabbed his weapon. Later, another man ran up and threw an object at the same attacker.

Lifeguards at the world-famous beach also headed to the area while the assault was under way.

The attack on a Hanukkah celebration by two shooters, which killed 15 and wounded several dozen, shocked the world. But the extraordinary acts of a number of people on the scene heartened many in Australia and beyond.

Their actions raised a question: How can ordinary people respond with such bravery?

Images of Ahmed Al Ahmed—a Syrian man who immigrated to Australia two decades ago and owns a tobacco shop in Sydney—tackling one of the attackers sped around the world quickly after Sunday’s assault.

“He didn’t think about anything else but to go and stop that person," said Tamer Kahil, a former president of the Australians for Syria Association, who visited Ahmed in the hospital where he was recovering from gunshot wounds sustained during the attack.

In speeches following the attack, Australia’s worst mass shooting in nearly 30 years, Prime Minister Anthony Albanese lauded the intervention of Ahmed and members of the Jewish community, including Boris Gurman, the retired mechanic, and Reuven Morrison, the man who threw an object—Albanese said he threw bricks—at the attackers.

Gurman and Morrison were killed in the attack.

“These are Australian heroes," Albanese said. On Thursday, he announced plans to strengthen laws countering hate speech and introduce new powers to cancel visas or reject applications for those who spread hate, part of a sweeping crackdown on antisemitism.

Albanese said Friday that intelligence officers had identified a regular online video feed from Islamic State that reinforces Australia’s view that the attack was inspired by ISIS, without providing any details on the video.

Social scientists say acts of heroism reflect the fact that, in emergencies, ordinary people often act more selflessly than one might expect.

In Hollywood depictions of catastrophe, people tend to panic, scream and clog the exits. “Good spectacle. But almost entirely inaccurate," said Stephen Reicher, a professor of psychology at the University of St. Andrews in Scotland.

Reicher cited a knife attack on the London Underground in 2015, where some people confronted the attacker while others attempted to distract him and direct people away from the area. During the Christchurch mosque shootings in 2019, an Afghan refugee threw a hand-held credit card machine at the shooter to give congregants more time to hide. During the Sept. 11 terrorist attacks, passengers and crew members resisted hijackers on Flight 93, forcing the terrorists to crash into the ground.

A 2013 review of 84 active shooter incidents in the U.S. from 2000 to 2010 found that in 16 cases, members of the public stopped the attackers.

“We should do nothing to question the quite remarkable bravery of people [who] intervened," Reicher said. “But we should also take heart that it is not the exception and that it reflects the very best of human behavior."

John Drury, a professor of social psychology at the University of Sussex in England, said his research suggests “the emergency itself changes relations between people." They often feel a sense of common fate. “Psychologically, they shift from ‘me’ to ‘we," he said.

Once he wrested the gun from Sajid Akram, Ahmed declined to shoot him, unwilling to contribute to the violence, Kahil said.

“He doesn’t want to kill," said Lubaba Alhamidi Alkahil, who is married to Kahil and runs communications for Australians for Syria. She visited Ahmed twice at the hospital.

The heroism by a Muslim immigrant has been a salve to intercommunal wounds. Australian authorities have said that the two shooters, who were father and son, were inspired by Islamic State.

“He saved the Australian Muslims from a miserable time for the next 10 years," Kahil said. “That actually turned things upside down from the Islamophobia perspective."

As more videos were released, other heroes emerged.

After Ahmed disarmed Akram, footage showed a man in a white shirt and a black hat running at the gunman and throwing an object at him. The man was identified as Morrison by Chanie Hebel, a longtime family friend.

“I can just imagine him with all his fury and his huge personality going after them," said Hebel, 30. “It honestly couldn’t describe him better. It’s just exactly what he would do in that situation."

Hebel characterized Morrison as “very much like a papa bear, a protector" who was very close to Sheina, his only child. She said he emigrated many years ago from the Soviet Union, where Jews were persecuted for decades.

“The first time I spoke to Sheina after it happened, she just kept saying, ‘I want this movie to cut. How is this real?’" Hebel said.

Dashcam footage from a passing car showed Gurman, the retired mechanic, attacking one of the terrorists and grabbing his weapon. He was killed along with his wife.

“This act of bravery and selflessness reflects exactly who they were: people who instinctively chose to help, even at great personal risk," according to a statement released by friends of the family.

Akram was shot by police and killed. The other shooter, his 24-year-old son, Naveed Akram, was charged by police with 59 offenses, including 15 counts of murder and committing a terrorist act.

Lifeguards, untrained in this type of disaster scenario, rushed to the scene, with some helping evacuate children from a nearby playground and others tending to the wounded.

“Our role is to run from the land to the sea to rescue people. The role was completely reversed," said Steve Pearce, chief executive at Surf Life Saving NSW.

The government has also cited police heroism in slowing the attackers. Two officers, Scott Dyson, 25, and Jack Hibbert, 22, were wounded in the gunbattle.

Hibbert had only been on the force for four months when the attack occurred, his family said in a statement released by police. He was shot in his head and shoulder, and lost vision in one of his eyes.

“For both officers, it will be a long road to recovery," said Mal Lanyon, the New South Wales police commissioner.

Write to Jon Emont at jonathan.emont@wsj.com, Mike Cherney at mike.cherney@wsj.com and Rhiannon Hoyle at rhiannon.hoyle@wsj.com