回复：hit someone in parking lot

First, it was not nice to augue with an old lady, expecially you might be at fault.
Second, it looks like the old lady was not injured, so it was just an auguement.
Third, if the old lady went to the hospital and claim she was injured at that time or in a relatively short time soon after that, you maybe in big trouble.
Therefore, you should go back to the store do some investigation to find out if they did call the ambulance.