Pony tail

It was over before I realized what had happened. I was exiting the subway as a small child, maybe 4 or 5 years old with a pony tail of long frizzy hair was running toward the entrance. I saw her coming toward me smiling and then suddenly jerking back as she winced. The adult with her (the mother??) had grabbed her by the hair and stopped her in mid-race. The child turned around, her face asking the reason of the sudden pain. There was no answer from the adult. She just looked at the child with expressionless eyes. I saw the girl smiled a tender smile as if to say "I understand" as I walked pass the two.
The whole scene took probably 5 seconds.