No way he would be able to generate enough force to break a back window.

Yep. Only way I could see getting out, is if you push yourself up with two arms. You would have to push up hella far too, and even then, not entirely sure if that would even be enough leverage

the diagram is certainly terrifying

I can see a skinny kid being fucked in a situation like that.

Such a tragic loss of life. Lose your kid because of something like this and emergency responders don't even come to help your kid.