Stewart Arroyo realized he had made a mistake when he heard a roar coming from AmericanAirlines Arena on Tuesday night.

He was crossing the street toward Bayside, along with his three nephews and dozens of other fans who left in the final minute of regulation in Game 6 of the NBA Finals. They assumed the Miami Heat’s season was over.

“Someone looked at his smartphone and said, ‘They just tied it up!’ ” Arroyo, 45, said.

Moments later, fans rushed back to the gates and tried to convince security to let them in. But they were denied, and had to watch one of the most epic victories in sports history on the monitors in front of the Heat store.

Photos and videos circulating online showed throngs of fans pouring out of AmericanAirlines Arena in the final minute when the Heat trailed by five points.

A sullen silence had engulfed the arena, some fans said. And few expected the Heat to force overtime and eventually beat the San Antonio Spurs 103-100 to force Game 7.

The early walkout has led to derision from Heat haters across the nation and soul searching among Heat fans, who have gained a reputation for being fickle.

‘THIS IS MADNESS’

Channel 10 reporter Victor Oquendo, who witnessed the commotion of fans trying to re-enter as he set up for a live shot outside the arena, tweeted Tuesday night:

“I was born and raised in Miami. I used to hate the national perspective against Heat fans but I can’t fight it anymore. Now I’m watching horrible, drunk, quitting fans desperately trying to get back in. This is madness.” His tweets were picked up by national media and was trending in Chicago.

Danielle Calixto, who was sitting in the lower level behind the basket, said she watched overtime surrounded by dozens of empty seats. She said she was disappointed with the lack of support but not completely surprised because she had witnessed early dismissals during other games this postseason.

“You don’t see that in other NBA stadiums,” she said. “They need to become better Heat fans.”

Arroyo, who sat in the second level behind the Spurs bench, said he left early because he didn’t want to endure the pain of watching the Spurs’ celebration and trophy ceremony like he experienced in 2011 when the Dallas Mavericks clinched the championship at the Arena, also in Game 6.

“I was screaming my head off the whole game,” Arroyo said. “To watch TV at home and criticize somebody for leaving early is wrong. It doesn’t mean you are not a good fan.”

A BAD POLICY?

Arroyo disagrees with the team’s no re-entry policy that prevented him from watching overtime.

“I have no idea why it’s implemented,” he said. “What happens if you have forgotten something and need to come back?”

Lorrie-Ann Diaz, the Heat’s director of marketing and communications, said the policy is an industry standard. Signs indicating “No Re-entry” are posted on doors throughout the arena.

Off-duty police officers working near the arena responded when they saw the commotion at the gates, but fans who tried to re-enter did not engage into any kind of altercation, City of Miami police officer Kenia Reyes said.

When the game ended, Arroyo and his nephews celebrated with thousands of ecstatic Heat fans exiting the arena. He said he felt somewhat guilty because his nephews missed the overtime because of his decision.

“I was very happy but mad at myself for leaving,” he said.

Miami Herald Reporter Rohan Nadkarni and Public Insight Analyst Stefania Ferro contributed to this report.