How did Sophie ... (spoiler)
How did Sophie get out of the shed after Alice's brother had locked her in? We saw him lock it. The window definitely wasn't smashed until the father did it, burning himself.
Also, Lena Garber's body was put in the shed by Getterick around the time Sophie left for medical help. So Sophie was sleeping next to Lena's dead body in the shed for a few nights? It was a tiny shed, I'm sure Alice's parents would have seen the huge corpse laying next to Sophie when we saw the parents stood at the shed door talking to her in the morning?