Wouldn’t sacrificing someone who can resurrect be too easy?
Sure, it’s a 'noble sacrifice', but they know they’ll revive later. What about the ones who don’t have spare lives? Would you blame them for not dying when they can’t even revive unlike you? When they also shoulder the fate of saving another world and prevent the apocalypse, but don’t possess the power of regression, so losing their life to save 50,000 would put a definitive end to their journey?
Sometimes, the lesser evil can be to selfishly stay alive. Dying now would be 'easier', but once they’re not there, the world and their precious companions would perish since nobody else could stop the end of the world (so these 50,000 will still die anyway).
It may seem cold, but you can save so many more people later by staying alive now.
