I'll agree with 'hard hearted' - because you can't watch them 24/7, not even close to that. First, you need to sleep. Then, you need to once in awhile feed yourself and take care of basics of hygene, and cleaning. And since a sane parent is better than one insane, a touch of time for yourself is good.
24/7, you do need to do your best to keep them safe - while you sleep, they're in a crib, while you do other activites, you put them somewhere safe like their crib, or with someone trusted. Sounds like, if this kid did escape from a carseat, or merely escaped from the car, the parents did put her somewhere safe, not knowing she would escape this time. But kids will surprise you here and there, with no advance warning that they're about to learn to roll off the couch, jam their fingers, climb the crib, etc. That's nothing like outright neglect like leaving them at the park or some such!
I'm a new mother too Shopper, and reading here is sometimes pretty scary, the level of condemnation for the lightest human error.