The red-shirt-wearing man shown in this video is holding on for dear life. Somehow he has a flimsy hold on the narrow gutter above the train through which water drains in the rain. It's too small and can't support a man's fingers and his entire weight. He struggles to hold on, switching his hands at the same time pushing against the jammed bodies of people to get in somehow. Nobody budges because there is no room inside. No, not even for him to get a toe hold.
What we see next is unclear as another man's shirt obscures the view. Then we see him fall. Imagine falling from a train speeding at around 100 km per hour. You strike the earth, and the impact can smash your skull. There is no immediate medical facility anywhere near stations. Another train has to come by and he has to be lifted on it to be taken to a station and then to the hospital. The victim will bleed to death mostly. Surely, he must be grievously injured or dying.
Then why did he take this risk? Why? Maybe, he is on his way for an appointment, maybe, he is on his way to see someone he loves. Who knows?
Travel safely in Bombay trains. If a train is crowded, please wait for the next one. All trains aren't equally crowded. The next one may be a local train that originated from the station next to the one you are standing on and, therefore, less crowded.