You'd have to factor in what percentage of people don't understand that if everyone picks red they all live. What percentage of people think that amount is more than zero, then what percentage of those people are willing to take the risk to save those people. Then what percentage of people are willing to take the risk to save the people that took the risk. And so on. Then if you care enough to take the risk yourself.

For me, the moral question is, why would I risk killing anyone? Even if I'm only one finger of many pulling the trigger, I don't want a part in it.

Why would you risk killing anyone? To save yourself; while knowing that your decision doesn't preclude any/everyone from saving themselves, and no one dying. Maybe you'd be the only person that chooses blue if it was a real scenario and each voters life was really on the line. Everyone saves themselves and everyone lives. Not saying it's the right or wrong choice.