Funny, not really

How might this happen?

Chad took the kids on a ride in the van one Sunday. Lia and I stayed home. He took them out to see if Utah Lake was frozen over, even telling Grace if it was, she could walk on the ice... OK this is very random but he was trying to bribe her into a boring car ride. They arrive. Grace and Chad get out to look at the lake. Kate and Jake stay in the van, all buckled. Chad returns to the van to find it locked. Car is running, Jake is playing a game on Chad's cell phone. It's about 7, dark and cold. Chad is in a t-shirt. No one is around. Closest house is at least a mile away. What to do? After waiting unsuccessfully for someone to drive by, or for Kate to figure out how to get out of her carseat, he smashed the back windshield in with a rock. Fun Sunday night outing. He really enjoyed telling me about it.