Innocent guy got slapped 3 times by a chapri auto wala.

I was walking near Austin Town(near neelsandra) when an auto lightly touched a boy (around 19-20 years old). The boy shouted a bad word -BSDK, and ironically, the auto driver started shouting back and even slapped the boy three times. The boy didn’t fight back because the driver was a local and might have a gang. One person stepped in to calm things down,acted to blame the boy and the driver left,later told him to be safe.What shocked me was how casual everyone else was—traffic kept moving, and people barely reacted. A local told me the driver was some wannabe KD-type. It really shows how poor law and order is in tier-2/3 areas of Bangalore.What should i do at that moment and what could you do if you were that guy? Obviously you cannot keep still as auto guy would have slapped 10 times here if not stopped.