Oh, that's an interesting theory. Would Sherlock have known that it was Irene on the phone? Moriarty didn't say, and the whole tangle with Irene came months after the pool happened, I don't know if he would have connected the two. I suppose he might have deduced it. Either way, I still wish she would have escaped by herself and let him know she was alive. It undermined everything they built up about her by having her need to be rescued.

I know he's only driving because Martin Freeman doesn't know how, but I just can't picture Sherlock going 'no, I'll drive' with John. Unless John can't either, or his licence expired while he was overseas. I would have thought Sherlock would need to sit and be able to look at everything.