Codrington was headed home from a party when he saw the 6-foot-tall man at the edge of the platform and then disappear. About 55 people are struck by New York subway trains and die every year, and the 24-year-old Codrington wasn't going to let this guy be one of them.
So he and the two others jumped down to hoist the bleeding, heavy stranger up — as the time clock flashed that another train was due in the station in one minute.
"It was really nerve-racking," Codrington said. "But we couldn't leave him there."
Miami emergency room doctor Ben Abo found himself in a similar dilemma at a New Jersey commuter train stop in Greenwich Village during his summer vacation to New York City. The 32-year-old was headed back to Jersey City, where he was staying, when a straphanger took an extra step and fell off the platform.
"He went down right over the edge. He was walking as if the platform was still there and wanted to take another step," Abo said.
The man fell head-first and lay on the tracks, bleeding heavily. Abo looked to see if a train was coming and jumped in, yelling for the two dozen people on the platform to pull a fire alarm and get help.
Sweating, he heaved the man up overhead, back onto the platform, as someone helped from above, and he then tried to pull himself back up, too.
He felt a gush of wind and saw headlights reflecting off the wall.
"I said to myself: 'You have one chance to get up,'" he said.
He made it and set to work trying to stop the bleeding, while a crowd gathered around him — holding up smartphones to take video.
Psychologists say some people have the right mix of qualities it takes for risky heroic acts — altruism, courage, knowing the right thing and being reflexive about it, as well as the ability to inhibit fear that stops most people from getting involved.
"It's not one hero gene. It's a very complex set of characteristics that converge and that person is unique, and thank God for them," said psychologist Dr. Rachel Yehuda at Mount Sinai Medical Center.
Ervin Straub, a professor emeritus of psychology at the University of Massachusetts, who has studied altruism extensively, said crowds in a big city can work against such heroism by creating a "diffusion of responsibility."
"When there are a bunch of people around, there is often a 'Why me? Somebody else can do it,'" he said. "But if someone else developed a strong sense of responsibility, they are not likely to wait. By seeing the others' passivity, their feeling of responsibility may kick in."
A gaggle of videotaping onlookers surrounded 44-year-old plumber David Justino this summer as he tried to stop a tourist from bleeding to death after an out-of-control taxi struck her, severing one leg and badly injuring the other. He used his belt as a tourniquet and poured bottled water over her severed limbs, which were gushing blood.