Man falls onto tracks in front of oncoming N Train

I was just waiting for the downtown N train at 8th Street in Manhattan. I had my eyes closed while I waited and as I heard the train approach, the train horn sounded and one of the people on the platform shouted! I opened my eyes to see the train halt mid-station and a crowd of people rush toward 1 car where they were saying a man was trapped underneath. I did not see him fall/ jump onto the tracks but one bystander said that he just got up and walked off the edge of the platform as the train came. Apparently he was responsive at first and everyone was screaming for him to remain still. Within minutes police arrived and asked the crowd on the platform, which now included all of the passengers who had been on the N train, to exit the station.

I went upstairs and waited to see if the man was going to be alright. Emergency responders- fire trucks and ambulances arrived immediately. Within 5 minutes they came up the stairs with the man on a stretcher, and before I could avert my eyes, or remove myself from the situation, I saw that he had no legs. Presumably the train had severed both legs at the knee. I could not tell if he was alive, but that image of the torn flesh will remain in my brain forever. God help this man.