So I've read many theories about all the time paradoxes of the Fringe season 5 ending. But what I can't seem to find an answer to is this:
Walter was supposed to take the last inoculation which enables him to travel to 2167 with Michael. But September took the last inoculation shot and decided to take Michael himself. Of course, September gets shot in the end and Walter Bishop is forced to take Michael to 2167 by himself.
What I don't understand is the inoculation part. Since Walter didn't get his shot, does it mean he didn't survive the trip? If that is so, then in a sense, September doomed Walter to not being able to travel to 2167.
However, we know that timeline did reset, so it means Michael reached the doctors and Observers were erased. Does this then mean that Walter did survive the time travel? If so, what was the point of the inoculation?