Reminds me of a similar situation that happened to me in Hong Kong last year. A family of 4 (husband, wife, kid, grandma) was a couple steps ahead of me on an escalator at Hong Kong Station. All of a sudden the grandma loses her balance, falls backwards, and starts to tumble down the escalator taking the kid with her. They landed on their backs and luckily I was able to react quick enough and prevent their heads from splitting open on the edge of the steps.