Wow. To be honest - I really enjoyed the episode as I was watching; I felt like it was a great return to the original style of season 1, it wasn't all campy like Empty Hearse, and it felt good that Mary was different to the typical portrayal of her as the epitome of domesticity. But now that you've pointed out all these plot holes, they're glaring at me, and I can see that beneath all the polish and prettifying, there are some huge problems with the way this ep was written. Wow.