But the episode is titled "The End" and some things will be ending. I have a hunch that I know how things will play out in at least one respect, but -- even though I'm simply speculating -- some of my friends who read this have not seen any of the current season yet and I would like to not drop a bunch of spoilers on them.
Thus, I am typing a lot of text ahead of the cut tag. :)
Much of the current dilemma that the team is facing is due to Future Yo-Yo's prophecy/recollection that it is the attempt to save Coulson's life that causes the destruction of the Earth. They are now down to making a decision as to whether to use the Centipede serum to save Coulson's life or whether they should combine it with Odium to take down Graviton and prevent him from destroying the Earth.
Of course, they have misunderstood what Future Yo-Yo was saying.
It was the attempt to save Coulson's life that has put the SHIELD team into a position where their next decision can destroy the Earth. Saving Coulson's life is now the decision that prevents the Earth from being destroyed.
Because what destroyed the Earth the last time around the time loop was dosing Graviton with Centipede serum and Odium. Yes, it ends up with Graviton dead, but not before his powers are amplified by the Odium so that the berserker rage that it triggers gives him the power to literally shake the Earth to pieces.
If you hadn't tried to save Coulson, this stupid plan wouldn't be an option. (And someone there should be smart enough to figure out that this is a stupid plan. I'm just not sure which one is going to figure it out first.) And that's what Future Yo-Yo was saying. It all went wrong because you tried to save Coulson. If you'd just let him die in the first place, this couldn't have happened.
But now, saving Coulson is the winning move.
Save Coulson, Save the World.