Feel your pain. In your situation I would of moved my daughter and me to safe area, made all aware. Went and got a Range Officer or range personell and explained the situation. If none around, I would of walked "Politely" up to the individual and immediatly explained muzzle control and down range and asked if I could help. I would of expressed my concern and try and help educate the individual.
I was at my indoor range the other day. I had a friend I was coaching. As I stepped back and watched my friend, I noticed the lane next to me had a mand and woman. He was unsuccsefully trying to teach her to shoot. He started to move the pistol muzzle to the right. I immediatly called a "Cease fire"! Everyone else on the lanes, stopped. I stepped up and asked him to bench the pistol in a safe direction (down range). I stepped back and said all clear. I then introduced myself and explained why I called the cease fire, and asked if I could help. Of course at first he was upset and embarressed. But soon after talking with them and using a friendly and respectful manner, won them over and got to coaching them. Both was having a hard time since had little experiance and ended up helping them and keeping all safe. We became friends and I am meeting them next week to try and coach them some more.