Dudley Green stands by a memorial near the site of a vehicle ramming attack in Vancouver that killed 11 people and injured dozens, on April 29. He helped protect the man accused of carrying out the attack from an angry mob until police could arrive and take him into custody.Jesse Winter/The Globe and Mail

Dudley Green stared into the eyes of the man in front of him.

“Just move out of the way,” the man asked. He spoke nicely, polite amid the chaos that surrounded them.

Behind Mr. Green stood Kai-Ji Adam Lo, the driver of the black SUV that had just torn through a street filled with pedestrians at Vancouver’s Lapu-Lapu Day Block Party.

When Mr. Green wouldn’t move, the man in front of him began to weep.

“He needs to die,” the man told Mr. Green.

“I don’t disagree,” Mr. Green said, in as calm a voice as he could muster. “But now is not the time.”

Mr. Green had been sick all week but decided to get out and catch a bit of the end of the Filipino festival on Saturday, including the closing act, for whom he had once worked security. He was leaving when the black SUV came careening down the road lined with food trucks.

“Everything just exploded in a flash,” he told The Globe and Mail, in an interview on Tuesday. “And I can tell you, there was carnage. It was just horrendous. A horrible scene to observe.”

Eleven people were killed, and dozens more seriously injured, including a 22-month-old boy.

Mr. Green saw many of the victims. Then he saw a crowd of distraught witnesses converging on the driver, who was standing against a chain-link fence alongside a security guard.

Mr. Green, who is six-foot-two, walked over and put himself between the driver and the irate crowd.

“I stood up tall and said to people, ‘Hey, just calm down. Let’s wait for the police. Let’s wait for the police,’” Mr. Green says. “People were emotionally charged and very angry.”

Seeing a crowd converge on the driver, who was standing against a chain-link fence alongside a security guard, Mr. Green put himself between the driver and irate crowd.Jesse Winter/The Globe and Mail

In a cellphone video from the scene, Mr. Green stands in the centre of the crowd, blocking the driver with his body.

“He killed a two-year-old kid!” one man yells.

“Hey guys, don’t do anything! Stop it! Stop it!” says someone else.

Amid the melee, Mr. Lo stands wide-eyed and blinking, sometimes saying, “I’m sorry.”

One man tries to get at Mr. Lo from the side and is blocked by a man in an apron. Another attempts to get at him from the front and is intercepted and led away by a man in a safety vest.

“I just stood there and just talked to people and told them to be calm and try to calm down the situation, even though, inside, after I had seen all the carnage that had happened, I was a little bit beside myself,” said Mr. Green.

A bus driver who is active in his union and previously worked in security, he says he used his past training and experience to make himself as calm as possible, attempting to de-escalate the situation.

“I just knew inside who I am, and that’s the right thing to do. I figured once the police came, he would be arrested, and then that will at least lead to some kind of understanding.”

He said he knew if the crowd became violent, there would be video of that, too, and those who attacked the driver would be arrested and charged.

He told the man who’d asked him to move, “If I move out of the way and you do what you’re intending to do, who’s going to look after your family?”

Slowly, the crowd dispersed, and police arrived to arrest Mr. Lo, who is now charged with eight counts of second-degree murder. More charges are expected.

As videos of the driver circulate on social media, Mr. Green says he’s had friends and acquaintances from all over the world message him about what he did to protect the driver.

“I’ve had a lot of my Filipino friends actually call me and thank me for actually making sure that guy didn’t get killed,” he said. “And at the same time, there are others that said I should not have stopped them. I should have let the crowd just beat the crap out of him and maybe even kill him.”

Knowing that, Mr. Green says he consulted with his mother before agreeing to share his story.

“She said to me, ‘Son, you should never apologize for doing the right thing at the right time, and don’t be afraid to let people know that,’” he said. “Everybody has the ability to do the right thing at the right time. It’s their choice. Either they choose to or not.”