. >> meera thakrar is enjoying a day of sightseeing with her 4-year-old son krish and her mother. >> we pretty much had five and a half hours in the city. >> at the turnstile in kendall station, meera is carrying krish. her mom is lagging behind when meera sees a train in the station. >> i was all excited. oh, my god, the red train is right there. why don't we just go on this one. >> she doesn't realize the train is on the opposite tracks. mira tells her mom to hurry. then walks ahead to hold the door. >> i was in my own world. >> in an instant, she was off the platform. >> i just walked straight down there. >> krish hit this ground hard. >> i saw my son hitting head. >> they miss the potentially fatal third rail, but are trapped in a perilous spot. the next train is arriving at any moment. they desperately need help. >> there was no support to climb there and come out of the tracks. you really needed somebody to pull you up from there. >> then from out of the crowd, a man leaps onto the tracks. he grabs krish while other passengers pull meera to safety. >> my son was taken out right