An eyewitness is stepping forward for the first time with a detailed account of jumping in and helping moments after the blast. He spoke exclusively to NY1's Mahsa Saeidi. She filed this report. 

Mingo Shaver is haunted by what he witnessed on Second Avenue and 7th Street Thursday.

"Under the rubble I saw an arm and it was the worst thing I ever saw," he says. "It was just rubble. You couldn't even make out a restaurant." 

The Queens native, a technician with our parent company Time Warner Cable, was on a lunch break when he heard the blast.

Twelve seconds into cell phone video, you see him enter the screen.

"When I looked to my right, there was someone under the rubble right on the sidewalk," he recalls.

After taking debris off that person, Shaver went inside the building: a pile of twisted metal, wood and bricks.

He's seen helping one person exit. 

"I went back to the building and people were trying to come out so I was carrying them out one by one putting them in the street.

Shaver says he and a group of New Yorkers helped four people escape, but by the time two minutes had elapsed, Shaver says the smoke became so intense, he couldn't breathe. That's when he saw it. 

"It's actually making me nervous now thinking about it," Shaver says.

Three minutes and 28 seconds into the video, Shaver is pacing in front of the building. Police have arrived. 

"That's all I could think about was that person," Shaver says.

Shaver immediately told firefighters there was someone else still inside. What happens next, he doesn't know.