i think he reacted on the spur of the moment and although it isnt pleasant to shout at other peoples children like that, you are probably right, he probably had far more effect than you would have has if you had shouted
dont worry about the woman next to you, afterall she doesnt have a dd whos foot nearly got hit by a car
and i'm guessing you are shakey about what could have happened rather than him shouting. We all have close calls and its understandable you are shaky still