When a fully loaded L’Enfant Plaza escalator snapped with a bang, sped out of control, and injured six people after the “Rally to Restore Sanity and/or Fear” on the Mall in October, one rider stood out for his presence of mind.

A video of the incident captured by a Metro security camera and released last month shows a short, balding man in khaki pants and a denim shirt come hurtling off the broken contraption — but unlike most he does not run away. Instead, amid chaos and screams, he pivots and goes to the rescue.

The man’s identity is now known: Dentist Randy Widen, 67, an expert in teeth grinding, is the unofficial hero of the L’Enfant Plaza catastrophe.

The runaway escalator incident, described by many as 18 seconds of sheer terror, resulted from a brake malfunction and was the catalyst for an inspection of Metro’s 588 escalators. The probe revealed similar brake problems on escalators throughout the system, prompting a mea culpa from Metro General Manager Richard Sarles, who acknowledged serious shortcomings in Metro’s escalator maintenance. Bringing the conveyances into good repair will take years, he said last week.

For Widen, a Chicago native who has lived in the Washington area since 1969, the accident was a chance to do something for the city he’s been enamored with for decades — as well as being a bit of a thrill.

Widen recalls the atmosphere of the crowd moving into L’Enfant Station that afternoon as “a total party.” Spirits were high, people were calm. It reminded him, he recalled Monday, of the “be-ins” in 1960s San Francisco, where people would gather at Golden Gate Park in simple celebrations of togetherness and community.

Things grew slightly more ominous, however, as the crowd compressed and funneled into the station. All Widen could see was “people disappearing over the edge” as they stepped onto the escalator, he said.

As he joined the scrum, a tourist asked Widen if he rode Metro often. Since the system was built, he replied. For years he had a dental practice at 18th and I streets NW, where he enjoyed piecing together a tableau of the Washington political and social scene through chats with his patients, none of whom realized he was also quizzing their associates.

Then words popped out of his mouth that he would regret.

“Truthfully, I’m surprised this thing is moving. They break all the time,” he recalled saying.

“If I’d only kept my mouth shut!”

Within 10 or 15 seconds, he heard a sharp metallic bang and “the escalator goes into warp speed,” he recalled. For a split second, he thought the steps had gone flat, making a slide, and felt like he was a child again at Chicago’s Riverview Park.

Then reality set in, and as he neared the bottom he weaved around the bodies tumbling in front of him, like a football player escaping the tackle.

“It wasn’t women and children first,” he said. “Everyone was in the same boat and had to survive.”

After being thrown off at the bottom and landing on his feet, Widen turned and saw “this cascade of people” piled up behind him. Some were yelling for help. The escalator wasn’t stopping.

“I knew I’d made it,” Widen said. “So I ran back to the pile. I’d pull one person out, then go pull another.”

On the video, Widen appears to help at least five people out of harm’s way. When the film cuts off, he is still rescuing. He checked people for injuries, did not see anything serious, and headed home to Lusby, Md. Six people were injured in the incident and four were transported to hospitals, including one person with lacerations, according to Metro. “I was really lucky,” he said. “It could have been me under the pile.”