Raging. Would like to beat this person with a cold metal object.
Just remember, silence is what they want. I know you were scared but its always good practice to distance yourself from said person, while moving towards people or a crowd. I would have quickly moved close to the librarian instead of going out where you'd be alone. Heck strike up a loud conversation with her, and whisper your concern about him. Attention is the last thing a screwed mind wants.
Make life what you want it to be.