HERE BE SEASON 3 FINALE SPOILERS. I liked Mary, sure. She seemed cool, and clever enough not to be intimidated by Sherlock, and comfortable enough to not interfere with that important relationship between her husband and Sherlock. I was not expecting the international assassin reveal. For one thing, she didn't quite fit the "Angelina Jolie" mold we all have in our head of female assassins. For another, it's quite the revision. Mind you, Mary has almost no characterization in the original, so it's not unjustified. Of all the emotional scenes connected to this reveal (the apartment and the Christmas scenes stand out), the best is when Mary confronts "Sherlock" after she's shot him. There's this coldness, these two people who are both pretty amoral meeting one another on equal ground for the first time. But the most important part of the scene sits in the shadows, until the emotional subtext literally takes shape when John stands up. We and Mary realize that he heard everything, that he knows everything. There's no going back to the status quo now. Mary and John are both heartbroken before our eyes.