Well, for one I can argue "There can be more than one outcome. Example: In this laboratory experiment about quarks in particle physics, they tried to keep all the variables the same but the outcome keeps changing." We've tried this before, but you guys just reply with "Obviously, they didn't do a good job of keeping all the variables the same."
You guys can attack me by saying that my "fake" free will has nothing to do with "true" free will, and say that I'm wrong if "a specific event can only have one outcome."