What are the chances of dieing in this Mos in the Marine Corps?

You don't need 20/20 vision to become an MP. I was in a MP unit for over 2 years, and a couple of the guys were even more blind than I am. Is it that your vision is only CORRECTABLE to 25/25? In that case, you need to get a waiver and you would probably be all set. I needed a waiver to join because of my vision.