Remeber, Ann is in another country, and may have different expectation or experiences with response time.

If I had been there, I would have called 911 - told them the situation and place, and asked how soon they could get there. Then absolutely, if the children seemed desperate, I would have found a way into the car. I would have also screamed at the top of my lungs for anyone in the area to come help, and to see if they could find the mother. I would have tried all the doors, tried to pry down the window, and if all else failed, spoken to the older child to comfort and inform that help was on the way if he was conscious, told the little one to cover his eyes, and I would have broken the wiindow furthest away from the children, and at least gotten them out of the car into cooler air while the ambulance came.

But that's just me.