Heart surgeon Dr. Ryan Chiu says he "just happened to be walking out" when he saw runner Tuan Pham stumble and collapse to the ground.
The owner of the mariachi school is still open and running his business by continuing classes via livestream video.
An ex-gang member from SoCal, who served five prison terms, turned his life around and is now helping others. He went back to school to get his master's and created a nonprofit to help the homeless on Skid Row.
