'Died from nuke in London' is a vague thing, but even if you choose a boundary by which to delineate it, that partition does not carve reality at the joints. There would probably be intermediate states of some measure where you suffer but live for some time after the initial blast, and probably be states of lesser measure where you are unharmed or even gain from the blast.

It might still turn out that the measure/probability/whatever of the suffering states is low enough that it's still worth leaving yourself open to being nuked, though. Like, maybe P(Alive|Nuked)=10^-5 and that's an acceptable proportion of worlds where you live through the nuking since you do successfully die in the vast majority of worlds. But if you're not sure, all else being equal, you'd want to pick the place within London that would be most likely to kill you if a bomb hit, rather than some obscure, heavily-sheltered place on the outskirts where you'll just about live and suffer after the blast.

In general, it's pretty suspicious if death seems to be the fundamental deciding factor in such matters (e.g. whether to live in London, whether MWI vs. Copenhagen matters); the reason people suspect so is anthropic--we can't observe (parts of) worlds where we are dead. But since 'I' and 'dead' are going to be fuzzy notions that do not carve reality at the joints, we should not expect them to be fundamental to decision-making in multiverses, even if they are efficient shorthands. It's important to bear this in mind with MWI and anthropics.

(yeah, I know - finally a reason for rationalists to move to the Bay Area)

lolol