You are absolutely correct, except for one big thing that i didn't really speak of. Lets say that this world was splitting in two. Two majorly different worlds/futures/universes.
Then, in one world, all A die, and B continue on. And in the other, all B die, and A continue on.
All the people who don't want to be in that new split off world, die. Because, we aren't really comfortable with half of the people just disappearing, or turning to light and fading/flying away, or turning to dust.
These worlds are actually splitting off right now.
And the healing work right now will decide what universe you will live in, in the future.
It will be harder and harder to shift timelines as they get further apart.