For two movies the John Wick franchise put Keanu Reeves' character up against basically the entire criminal underworld, of which, there is quite a bit, with little to no assistance. However, in John Wick: Chapter 3 - Parabellum, John gets a little bit of help. Some of that help comes from Halle Berry, who is introduced in the new film as Sofia, an old friend who owes John a debt.
Sofia comes from the same world as John Wick, and that means Halle Berry had to go through the same rigorous training to make Sofia look like the some brand of badass that John Wick is. However, Halle Berry admits doing so wasn't easy. She, personally was no fan of guns, to the point that she apparently broke out in hives during her first training session. According to Berry...
The first session I had I literally broke out in hives. I was uncomfortable holding something so powerful, and a bit afraid of it.
We all love some good old faction action in our movies, but for many of us, there is comfort in the fact that it is all fictional. Even holding a prop gun allows for a degree of separation from the real thing if an actor needs it, but training for John Wick movies is much more real, and apparently for Halle Berry, things were actually a bit too real.
While the action scenes in John Wick movies are highly choreographed and stylized, the weapons training is done to make the handling of the weapons look as authentic as possible. That means real guns.
Eventually, Halle Berry says in the special features of the John Wick: Chapter 3 Blu-ray, that, while she clearly hasn't changed her tune on guns in the broad sense, she was able to get through the training by focusing on the fact that, by learning how to properly handle a gun, she would be in the best possible position if she were ever absolutely forced to use one.
What helped me was, I connected to thought that, while I'll never own a gun, I have two small children, and if someone ever pulled a gun on me, now I would know what to do with it if I was lucky enough to get it away from them. And with all of my other John Wick training, I might get it away.
Hopefully we'll get to see Halle Berry put all that training to good use again. John Wick: Chapter 4 is on the way, and so there's always the possibility that we could see Sofia again. Clearly, whatever Halle Berry's feelings about guns, she learned how to use them quite well. Sofia looks to be as skilled with a gun as John Wick himself. If they wanted to give Halle Berry a spinoff, there's no question she could pull it off.