You know what was unnecessarily cruel? Mary at Leinster Gardens after shooting the coin. She kicks the coin over for Sherlock to pick up. The man she shot a week earlier. The man who should still be in hospital. She makes him bend over, putting pressure on his bullet wound. She doesn’t care that he’s hurting. She still needs him not to tell John but acts as if she wants him to physically hurt. She still needs something from him yet she treats him like garbage. This is not what a kind woman looking for redemption does. She is cruel. She is written as a cruel character. She is cruel in TAB. She will continue to be cruel in S4.
I can concede that Mary could have shot CAM and still have been a good person. I can believe, given her background, that she would’ve felt that was the only way to do things, if she was doing it to protect others. Maybe not a morally good option, or the best option, but it wouldn’t immediately make her a villain.
And if the writers had chosen to go that route, killing CAM to protect family, she still could have been a good character. How do I know? Because that’s exactly what they did with Sherlock when he eventually kills CAM. At some point, both Sherlock and Mary make the decision: “Magnussen is a dangerous man and I need to stop him.”
So it speaks volumes that the writers instead had Sherlock interrupt Mary’s assassination attempt. Because now Mary is placed in the same position Sherlock will be placed in: killing in front of a witness. No longer can she do this in secret and return to her seemingly normal lifestyle.
In that moment, Mary is given a choice. Either she receives Sherlock’s help and/or shoots CAM, knowing that John will find out, or she shoots Sherlock. John will not listen to CAM unless given a large body of undeniable facts, but he will believe Sherlock far easier, especially if he makes it up there in time to see her in the black outfit with a gun. But if she shoots Sherlock, she can avoid John finding out and try to deal with CAM later, knowing full and well that CAM will continue to harm her family and other innocent people if she lets him go.
Mary must chose between protecting others and protecting herself, and she chooses herself.
Then Sherlock is given the same general setup. He has a witness (several actually), and if he shoots CAM he is placing a sentence upon his own head. However, if he lets CAM go, CAM will continue to harm others, including John.
Sherlock must chose between protecting other and protecting himself, and he chooses others.
That what I mean when I say “Mary is a villain because she shot Sherlock.” Not “where did she shoot him on his body” or “let’s go through a minute-by-minute discussion on whether Sherlock actually died”. Mary was given an option to take down CAM with Sherlock’s help, and she placed her own life’s value far above Sherlock’s, her husband’s, and even her unborn child. And yet, given the same choice, Sherlock gladly and without hesitation throws away his life to save others. Mary is selfish and had no intentions of protecting others by shooting CAM anyway, if she did she would not have decided that continued secrecy of her true identity was the most important value to her. She is a villain just as much as Sherlock is a hero, and that wouldn’t change no matter how many times John forgave her or how surgical that chest wound was. Mary made her choice, and she is not a bit sorry for it.
When Moriarty says “that wife!” it means even to Moriarty Mary is a force to be reckoned with. It means in Sherlock’s mind, Moriarty would pause at the villainy she commits. In the darkest corner of his soul, Sherlock sees her as comparably dangerous to Moriarty. She is not a damsel in distress. She is not looking for redemption. She is the reason John Watson is definitely in danger.