User blog comment:DiegoAnime3000/A lot headcanons were confirmed today/@comment-4909254-20140829013601/@comment-3257939-20140829022501

You can clearly see that she touches the soda in the floor and sends her polarity to all those cans covered in the same soda. That's how she easily moved that army. She touched Mercury's boots with her own weapons which are made of metal. Both water and metal are conduits for electricity which is how her magnetism works.