In cinema, a writing instrument being used as a weapon is not uncommon. Normally, this occurs when the writing implement is in the hands of, say, an experienced killer:
3. Jason Bourne uses a pen to gain advantage in a fight in The Bourne Identity.
2. Martin Blank uses a pen to kill a man in Grosse Point Blank
1. The Joker’s pencil trick from The Dark Knight
But, I’m not sure how this case fits into all this.