It is true that you should try to remove yourself from the threatening situation as quickly and with the lowest level of force possible. In my state, however, if you are attacked in your home you have a right to stand your ground. Out of your home if you can run and don't run you are liable for any damage you do to the person. As for being treated differently by the law, the answer is yes, and no. The law will look at your ability to defend yourself with the least force needed. If you are a strong untrained man and are attacked by a weak slow person with a knife you don't need to kill the person to remove the deadly weapon. The same goes for the martial artists. If you have the ability to disarm and subdue someone attacking you with a knife, you should. If you use excessive force beyond your need to defend, the law is allowed to deal with you accordingly.