It doesn’t have to pick any specific one; any branch in which you’re alive will do.
That means it picks a branch at random, which contradictions Many Worlds' premise that the universe is fully deterministic.
Nobody’s really “jumping”, you just don’t die.
No, if it is real you are absolutely jumping. If I were to step in a cloning machine, there would be a clone of me. But that clone wouldn't be me because I wouldn't see out of the clones eyes. The clone would have its own experience and would go on to live its own, different life. If I suddenly died, I would not expect my consciousness to suddenly hop out of my body and take over the clones'.
If I died I would just die. The clone would live on because the clone isn't me. Similarly, the other "yous" in different branches of the wavefunction would basically be like copies of you. They'd not be you, they'd all have their own independent lives. If you died in this branch you'd just die. To claim you continue living in another branch is equivalent to claiming your experience somehow jumps out of your body and into a clone's.
It is a funny superpower idea. Like turning invisible. Which also doesn’t make any sense if you think about it.
I am just saying it doesn't actually make logical sense if you take it seriously as something real. If it's just a funny comic book idea then I have no issue with it, I'm just cautioning people to not think quantum physics actually does support the idea, because some people seem to think it does.