User blog comment:Essie Essex/Arkane Studios Announces Dishonored 2/@comment-26396097-20150807160551/@comment-5607198-20150808173722

this thread is a logical fallacy

The Outsider does not know the future.

From what we see, Billy can see CERTAIN futures, but not the "correct" one. He's obviously surprised by actions of human characters, and the people he sees as most likely to be capable to surprise him are the ones who recieve his Mark.

Therefore, the ending slides are the 90% likely predictions of an unknowably powerful entity.