Rohan Dennis, casual in a red Bahrain-Merida t-shirt, walked off his bus and straight toward a finish line he never crossed, flanked by his agent, Andrew McQuaid, and his press officer. Behind him, reporters and cameras trailed like the tail of a comet.

His Tour de France was over, and he wouldn’t say why.

Two hours earlier, some eighty kilometers into the 12th stage of the Tour, at a feed zone, Dennis had climbed off his bike and leaned it against the back of a Bahrain soigneur car. His first team car was ahead, behind the break, and the second car, the one behind the main peloton, drove right past him.

It parked further up the road — you can’t drive backwards on the Tour route under any circumstances — and sports director Gorazd Stangelj ran back. “We tried to speak with him,” Stangelj said, standing in a ten-deep media scrum outside the team bus after the stage. “We stopped the car and tried to find a solution to what’s going on. But he would not talk.”

It was Dennis’ decision to stop in that feed zone, Stangelj said, and his decision alone. The source of that decision remains murky. Dennis hasn’t spoken publicly since dropping out. He didn’t stop when he came out of his bus Thursday afternoon. Text messages to him have gone unanswered. There is no official explanation. He is not sick; he is not injured. And so nobody knows, not for sure anyway, why he stepped off in that feed zone.

“For sure it’s nothing to do with his physical condition,” Stangelj said.

We do know he has genuine problems with explosive, angry responses to relatively innocuous challenges. He’s a hothead. Former teammates, managers, team staff – it seems everyone has a Rohan story. Each rider or team staff member I contacted in the last few hours said some version of the same: Yes, it’s a problem. This isn’t the first time. It’s a pattern.

“He needs help,” two former teammates told me, asking that I not use any specific stories they’d told. It’s a phrase that turns this story from one of bemused confusion — why would an elite athlete do that? — to one that feels quite sad.

There were rumors of an argument at the team bus this morning. Orla Chennaoui, a presenter for Eurosport, said she and her team witnessed “obvious tensions” between Dennis and his team. Stangelj said there was no argument this morning.

We know that Dennis has had issues with his time trial bike all season. He said as much to Neal Rogers at the Tour of California. But then he took a time trial win at the Tour de Suisse, the first for his new team and the first on that bike. You’d think that would have repaired the technical relationship somewhat. Belgian media is now reporting that these TT bikes issues rose again ahead of Friday’s Pau time trial.

Reporters peppered Stangelj, the Bahrain director, with questions about Dennis’ satisfaction with his equipment. “I don’t know anything about that,” Stangelj said.

Was Dennis sent back for bottles, or some other duty insulting to a rider of his caliber?

“No, I never asked him to bring the water in the race,” Stangelj said. “Actually, I even said to him for the last two days, yesterday and today, to save energy for tomorrow, for tomorrow’s TT.”

Stangelj did his best to explain without quite explaining anything.

“He is a special guy, let’s say. All the champions are,” he said. “He’s really 100 percent when he wants something. It’s difficult to make everybody happy in every single moment.

“He’s the guy, he wants to have everything 100 percent. It’s not easy to have everything 100 per cent.”

The specifics of the slight are largely irrelevant to the end result. This is a rider who made a decision on the side of the road to pull himself out of the world’s biggest bike race, on the eve of his best chance to win a stage, with no apparent physical ailments of any kind. There is no argument with management, no spat with a teammate, that justifies that decision or makes it rational.

Because it is irrational. It is sad. A young man’s Tour de France is over, and for what?