So a friend of mine had a dream and she is interested in the interpretation of it. All ideas welcome:

I will call my friend Wendy.

In the dream an ex roommate of Wendy's, who in the dream was not her roommate, was running around the city stabbing women. We'll call this roommate Mary. In real life Wendy can not remember ever having an issue with this girl. Anyway, in the dream Wendy is sitting at the dinner table with her mom and cousin. Wendy sees Mary running to the table, at the end of which is a sharp knife. Wendy runs and grabs the knife first and then immediately wakes up. Wendy feels like she might have won but also had the impression that Mary was going to win by overpowering her, grabbing the knife and stabbing her and her entire family.

What could the meaning be?