BUY ME A CANDY BAR!

At the grocery store, Judy screams at her mom Amy to buy her a candy car. Amy refuses b/c it is unhealthy, w/ Judy throwing grocery items, calling her mom stupid, rolling on the floor, saying she will stop once she gets her candy bar. Amy is ashamed of being such a weak mom that she can't control Judy, w/ Amy stammering Judy to stop, and Judy getting more and more loud and out of control. Will you intervene or do you just keep your head down and continue shopping?