you get inconsistencies very rapidly once you have one of those agents stuck in two Prisoner's Dilemmas at once.

Multi-player interactions are tricky and we don't have a good solution for them yet.

that's willing to give up everything else of value (e.g., billions of human lives)

It's not that its willing to give up everything of value - it's that it doesn't have our values. Without sharing our values, there's no reason for it to prefer our opinions over sea slugs.