Ok, first please read the thread I linked to.
Now imagine you were the big bald guy.
Now imagine this guy just broke in your house and has distance on you.
Do you see a problem yet?
Additionally, it takes years of practice to become proficient at a martial art. It is not something that you can take a few classes on, then be qualified to defend your home with.
Why do people always forget that wolves will never give up their fangs?