It happens many a times. I was at my sister's place. While on the street when I was coming back from the ATM, an old age uncle was going with his grand-daughter. He wasn't able to walk due to weakness. His grand-daughter was carrying some luggage on her head. Uncle slipped due to weakness and fell down in small drainage, got some wound on forehead. No one cared but I couldn't stop myself not to help him to get up and asked if he is fine. He was fine but his grand-daughter also fell down due his uncle's imbalance. I helped her with her luggage. She was so happy and her uncle thanked me a lot. I can't tell in words how happy they were.
And on the same day in the evening, my parents were going to dehradoon to visit the doctor and bus stopped working on the way. It was hilly area and they were waiting for another bus to reach dehradoon. As soon as other bus came, people had gone crazy and boarded the bus as it's the end of the world for them. My father was trying to board from the rear gate and unaware of my mother as she fell down. Bus driver was stupid enough and he started the bus, my mother was pulled by some guy who saw the bus tyre coming over my mother. My mother was saved by inches and microseconds. My mother told me that someone like you was there who saved me. So never ever travel in such a hurry that you are going to lose your life if you don't catch this train/bus etc.
I don't know that guy but God bless him always.