You want to kill a monster? Fine. But prepare yourself, you’ll need to become a monster as well.
Okay, so I know there has been much debate over this. I personally think she did try to kill him, without killing him. Confused? Let me explain.
In this situation I have come up with 8 possible solutions and 6 likely ones. I will explain 6 because 8 and 9 have to do with unicorns and man-eating wallpaper.
1. Mary kills both Magnussen and Sherlock. This is the best solution, seeing as Magnussen would no longer be a threat and Sherlock couldn’t tell John about Mary because he would be dead. But, sentiment got involved. John would be blamed for both murders, and Mary couldn’t let that happen.
2. Mary kills Magnussen and leaves Sherlock alive. This is a good solution for the Magnussen problem but presents a challenge in that Sherlock would tell John what had happened. Again, not good for Mary.
3. Mary leaves Magnussen alive and kills Sherlock. Good for John not finding out, bad for Magnussen getting away.
4. Mary shoots Sherlock, but does not kill him knocks Magnussen unconscious. This is the solution she ends up going with. Magnussen gets away and Sherlock lives to tell John the truth. Kinda bad all around…
5. Mary knocks both Magnussen and Sherlock unconscious. This is the best option in my opinion next to the first. It leaves both alive and it’s exactly like option 4 except less lethal for Sherlock.
6. Mary shoots Sherlock, Magnussen, John, and herself. Horrible solution, no explanation needed.
So it seems to me like option 5 is the best way to go, it leaves Sherlock alive just like option 4, just with less chance of a dead Sherlock…So why didn’t Mary choose option 5? I mean she is a trained assassin, she’s used to thinking fast. It’s not like it didn’t occur to her just to knock them both out. The outcome is the same on both, its just that Sherlock would have a greater chance of living with option 5. She could easily knock Sherlock, being an assassin and all. So why didn’t she?
I think she wanted to give Sherlock a chance of living. That’s why I think she didn’t go for a kill shot. She wanted a clean conscious, like if he bled out it wasn’t her fault. She called an ambulance, tried to save him, and if he died, oh well.