PARIS — Hands on his head, tears in his eyes, Mozambique sprinter Steven Sabino walked off Stade de France’s distinctive purple track and disappeared down a tunnel.

The 18-year-old could scarcely believe that he would fly back from the Olympics without even getting to compete.

Only moments earlier, Sabino was at the start line for the second heat of the men’s 100 meters prelims, but he sprang out of the blocks before the starting gun sounded. Track officials ruled that he false started and showed him a red card indicating that he had been disqualified.

“We went into a set position and I heard a bang,” Sabino said between sobs 10 minutes later. “I don’t know where it came from. Probably the pole vault. I don’t know. I heard a bang, the kind of bang that you hear when the electronic gun goes off.”

Sabino briefly pleaded his case to track official Vadim Nigmatov, pointing to his ears to indicate what he’d heard. He said that he asked to run the race under protest, but Nigmatov and the other officials refused.

“They didn’t even hear what I had to say,” Sabino said. “I sacrificed everything for this.”

Sabino’s plight is the latest reminder that track and field’s zero-tolerance false start policy might be the cruelest, most unforgiving rule in sports. It’s more sudden than a sixth foul in the NBA Finals, more damaging than a red card at the World Cup and more common than an unsigned scorecard at one of golf’s majors. It has induced tantrums from otherwise mature adults and waylaid some of the legends of the sport — even the great Usain Bolt.

Only an hour after Sabino’s false start, the rule took out another runner. Great Britain’s Jeremiah Azu false-started in his round 1 heat and also was disqualified without getting to run.

Azu, like Sabino, said he “heard something and just reacted.” He planned to appeal his disqualification in hopes of being granted a chance to run by himself and try to qualify for the Sunday’s semifinal on time.

“Right now, I’m acting as if I’m running again,” he said

International track and field’s governing body went to a zero-tolerance false start policy over a decade ago out of a desire to streamline the sport and eliminate gamesmanship.

Under the old rules, sprinters or hurdlers notorious for slow reaction times would attempt to gain an edge by guessing when the starting pistol would fire, knowing the penalty would be charged to the field rather than to themselves. The multiple false starts slowed down meets and made it difficult for TV networks working within a specific time slot.

In their zeal to make the sport more TV friendly, World Athletics officials also risked depriving viewers of the chance to watch a marquee sprinter race. Imagine the outcry if Noah Lyles or Sha’Carri Richardson sprang out of the blocks too early this weekend and received the red card shown to Sabino.

Sabino said he has dreamed of running on the Olympic stage since he began running track as an 8-year-old. He’s currently in 12th grade at a school in South Africa, juggling school work and his training.

“My marks at practice were showing what I wanted to see,” he said. “I thought this was my opportunity to show the world that I am capable and unfortunately it didn’t happen.”

The cruelest part to Sabino? This, he says, was his first-ever false start.

“The fact that this is my first one and it’s on the biggest stage …” he said, his voice trailing off.

Brutal. Absolutely brutal.