But what you can't rule out is that someone seeing Madeleine in a distressed state and taking her to get medical or palliative treatment.
If someone had sedated her up to the eyeballs prior to bedtime I don't see how she would have been wandering around, but anyway.
If she'd walked and wandered in a distressed state, as you suggest, and had taken her for medical care... assuming someone wouldn't have administered first aid while phoning for an ambulannce... then what? A doctor, medical clinic or hospital simply forgot that a young child had died and didn't bother to contact the police?
What do you mean by taking her for palliative care as opposed to emergency medical assistance?
I suppose there's a remote possibility that she woke and wandered and was the victim of a hit-and-run... who then came back to pick her up, but what evidence would one expect to find if that had been the case? And was any found to support that theory?