The Daily Mail interviewed January Jones, and she said the toughest stunts involved the wire-work with Michael Fassbender:

I was nearly decapitated by the stunt wires in X-Men.

The most difficult stunts were with Michael Fassbender, where I was spinning in the air on those wires. While my stunt double did a lot of the harder stuff, I’ve always been very sporty and the stunts and action are part of the fun. As Emma Frost I’m telepathic, and I can turn into a diamond, which means I’m very, very cold. I always wear white: lots of iridescent stretch leather, lots of sparkle, and ass-kicking white boots.

So, we now know Emma gets at least two battle scenes with the top dogs of the movie: Xavier and Magneto!