We aren't talking about changing the story of BP3, which is already written out. We only talk about the subtitle.
"Falling Towards Apotheosis" would mean someone getting closer to becoming a divine being, wether they want it or not. That would fit the situation of the Humans quite well, since they are manipulated by the Vishnans for sure and most likely by the Shivans too (Ken being the most obvious hint in that direction).
And "Into the Fire" could just mean as much as "There will be a massive battle"... which will probably be the case in BP3.
Neither of those subtitles has anything to do with Babylon 5, beyond being used there as an episode title too.