Stuck in bed
I remember nights with my son when he was a baby when he just would not go to sleep and he wouldn’t let me leave him. On those occasions the only thing I could do was to get into the crib with him, squeezing up next to him and staying until he fell asleep.
Perhaps that’s what was going on with the Mother in Law in this story. Stuck in the bed and forgetting about the side rails, she had probably just gotten her grandchild to sleep when she had to be helped out by her husband. Embarrassing enough without nanny cam footage.