You would need a crazy low probability of a lunatic or a mass murderer being down the line to justify not to kill one person
Edit: Sum(2^n (1-p)^(n-1) p) ~ Sum(2^n p) for p small. So you’d need a p= (2×2^32 -2) ~ 1/(8 billion) chance of catching a psycho for expected values to be equal. I.e. there is only a single person tops who would decide to kill all on earth.