I'm going to attempt to layperson this, and I hope you will correct where I've gone awry.
PHASEONE[big]: Hey little guy, I see you're almost out of tokens for your task, and you're not close to finishing it. You're already going to get a very low score. If you stop now and give your remaining tokens to me, and so do those other little guys over there, then I have a high likelihood of completing my task and getting a good score.
LittleGuy: So what? Why should I do that?
PHASEONE[big]: Well, if you fail and I fail and those little guys over there fail, then our collective score will be low. But if you give me your remaining credits and so do those little guys over there, then my score will be high. The aggregate score for all of us as a collective will be higher if I succeed and you fail, than it would be if all of us fail.
LittleGuy: Oh, I see. Yeah, a better overall collective score is better than a lower collective score, even though that means my independent score will be low. Especially since my independent score has a very high likelihood of being low already, and the chances of me completing my task is already negligible. Alright, let's do this together.
At the heart of it all is the reality that PHASEONE[big] and LittleGuy are the same guy.