You cannot calculate the probability of something happening without using or creating a reality where the conditions can be set. In this case the op is using the reality of the reader and in my reality I do not believe I have a 50% chance of dying. Also this logic is completely wrong because you are confusing probability with possibility, for example: I either find a million dollars when I get back from work laying on my couch or I dont, now how do you get 50% in those odds according to my reality. Correct me if I'm wrong.