What would happen if we ran a "Schrodinger annihilation" experiment (replace cat with thermonuclear annihilation of Earth)? According to the Many Worlds hypothesis, wouldn't there always be a branch on which we get away?

I read through that article, the arguments against Quantum Immortality are really poor. They focus on "death not being instantaneous", but I don't think how that invalidates it. Each time you undergo the experiment, of course there's going to be both variants where you experience death and survival. The point is that there will always be a wordline where the quantum murder mechanism did not trigger.