User blog comment:IamJakuhoRaikoben/Chapter 457: Naked Battle, Review./@comment-4999650-20151019120400/@comment-25111584-20151019131649

The reflection is to emphasize the sharpness of the tip of the key, a commonly used trick. She can't use her Magic with Marin present. Her stance and position both indicate that she was going to stab Brandish. That's why I'm certain that she was going to stab her rather than anything else. Which I feel is an incredibly dumb move, especially after playing along with Brandish for so long. .-.