The surveillance camera is perfectly placed to show the man walking along a nearly empty Metro platform. He steps sure-footedly across the distinctive hexagonal flooring, moving into place as any waiting passenger would do. It’s easy to miss the white cane he sweeps and taps in front of him with confidence.

The man arrives at the bumpy strip of tile meant exactly for this moment: to warn the visually impaired that they are at the brink. He stops, tests his path carefully, seemingly aware of the void inches away. And then, for unclear reasons, he takes a further step and tumbles down onto the tracks.

“It’s a very hard video to watch,” said the man’s sister, Syl Higgins, a local fitness instructor. “You hear about things like this all the time, but when it’s your own brother . . .”

Higgins didn’t identify her brother, saying he was too embarrassed to talk about his chilling misstep Tuesday at Bethesda’s Medical Center station on the Red Line. Reached later, the man declined to speak Saturday about the incident.

Higgins said the man hadn’t told anyone in his family about the accident until a video of it began getting attention on social media a few days later.

Higgins first watched the footage Friday night, cringing at her brother’s peril, but then rejoicing at what followed.

Immediately after the man fell out of sight, a figure just visible at the far end of the platform starts jogging — and then running — toward him. Another woman who had been looking down at her phone halfway along, realizes the man has fallen and rushes to the spot. By the time they arrive, the man has gotten to his feet and has his arms on the platform.

But he’s a big man, and clearly shaken. The first rescuer pulls futilely at his arm. The woman runs for help.

The lights at the platform edge begin to flash. A train is coming.

But another man sprints down the platform, and another moves in from the opposite direction. As the lights of the oncoming train grow brighter in the tunnel, two women join them. Many hands find a place and, as the front of the car enters the station, they haul the man to safety.

“I am so thankful to those people,” Higgins said.

Metro officials said the man was taken to a hospital for non-life-threatening injuries and released.

Higgins said her brother is at the station weekly on trips to receive treatment for a rare eye disease that caused him to become legally blind as an adult. She wondered if he was under a medication that might have made him unsure of his footing. She visited him Saturday to hug him and tell him that he does not need to feel self-conscious about an accident that had a happy ending — and that proved he is surrounded by people willing to help.

“I want him to understand how much people love him and how much people care,” his sister said.