Don't kick yourself. It sounds like a freak accident. I don't think anyone has to mangle the legs. Snakes kill and eat. They don't break the legs. I've heard they can have a little trouble when you move up a prey size at first, but it gets easier every time. Mine recently got the nose of a mouse stuck in the back right of her cheek. Took her a while, but she got it down. I know that is quite worrying and I'd have been real worried if it took her an hour! Glad you also had a happy ending.