I'm sad to say that I didn't really like the ending of this episode. As I was watching it, I gasped and grinned to see Sherlock there, but when it ended I felt that ending to rather undermine Irene's brilliance. She wasn't able to escape without Sherlock's help. Perhaps I'm comparing this too closely with the original story? Maybe I shouldn't be too hard on Moffat et al, but I can't help but feel rather disappointed.