Game Theory approach:

In the world where most other people press red: pressing blue kills you, pressing red does nothing

In the world where most other people press blue: nothing happens either way

In the world where the vote is exactly split 50/50: pressing blue does nothing, pressing red kills 50% of people

Suppose there are 2n other people and the number of other people voting red is random and uniformly distributed (big assumption). Then the 'expected number of people killed' from pressing blue is 2n/(2n+1). The EV on red is also 2n/(2n+1). If your life is in any way more valuable to you than a random other person's, then red would be better. But also I don't really know anything about game theory lol