No one could imagine it? I remember a lot of stories about kids doing just that. Who leaves their kids alone that long? Long enough for one child to wake up, one to fall asleep, the first child to nearly kill herself, a stranger to come get her out and run for help, and then the mother to come back out. How long was that? 15 minutes? Longer? This is as far from a tragedy as you can get. It's neglect causing death.