By Jeremy Ross

CHICAGO (CBS) — A teacher, trained in CPR several months ago, used those skills to save a life Thursday.

The reason the educator had those skills is now part of a chain of life saving stories.

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CBS 2’s Jeremy Ross reports how one man’s medical rebound is helping others do the same.

Elston Harris says he played basketball all his life. On June 23, he black blacked out, his life nearly ending. HE says he suffered a heart attack.

“I was told I flat lined four times,” recalled Harris.

One reason he’s alive, he says, is a police officer at the basketball court who knew how to perform CPR.

Dr. Marlon Everett says Harris and Advocate Trinity Hospital have made it their mission to train tens of thousands of people.

“He immediately called 9-1-1 like he was supposed to do,” said Dr. Everett.

One of those trained is a teacher at Hyde Park High School, who claims the skills came in handy when he discovered a 14-year-old girl without a pulse Thursday.

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The 14-year-old had a severe food allergy, spiraling into not having a pulse.

“He did chest compressions,” said Dr. Everett. “He went at it, with the beat of 30 compressions until EMS arrived.”

“There’s like a rhythm involved to the song ‘Staying Alive,’ du du dah dah,” Harris hummed. “He really was a hero.”

The teen is rebounding thanks, in part, to the teacher’s actions.

A crisis once on a basketball court turned into a cycle of training and lifesaving.

“[I’m] passing it on and on to as many people as possible,” said Harris.

The 14 year old is expected to be okay.

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The hospital and Harris have a goal to train more than 70,000 people in CPR. Classes will be coming to Chicago area schools.