I think this could be a major reason such parents would stay in. To leave and accept the fact that you'd let a child die because you were following the interpretation of scripture of a bumbling idiot in New York who you've never even met would drive one to major depression or even worse.
One Jonestown survivor reckoned that Jim Jones ordered the children to drink the cool aid first because after you've seen your child die in your arms what are you gonna want to do even if you dont believe it?