This is a world where there are potions that can regrow bones in a single night. I think it wouldn't matter that much to Harry if he did lose his finger.
Thanks. My first reaction was just this seems too surreal. Any other story in which Harry Potter does not kills dementor and there's a reasonable explanation and laughter would have been my first reaction.
I thought that was because Tonks trained under Moody?
"Sign up for the Auror preparation program in your sixth year," said Susan. "It's the next best thing. Oh, and if a famous Auror (assumed it was referring to Moody?) offers to oversee your summer internship, just ignore anyone who warns you that he's a terrible influence or that you're almost certainly going to die."
This is a world where there are potions that can regrow bones in a single night. I think it wouldn't matter that much to Harry if he did lose his finger.