Game of Thrones final episode.

[Boomer]

11. Tyrion didn't betray Varys

The episode was really rushed and the nuances of Tyrion's dilemma weren't given even a token scene of drama, but he didn't really have any choice.

Varys was trying to poison Dany. He got caught. When you try to poison your own ruler, you die. We never saw the details of how Tyrion learned of Varys' plan, but the assumption is that he probably wasn't the only one who knew, so his hands were tied.

Apparently these scenes were so rushed that a lot of people missed the poison plotline entirely (it consisted of just a few sentences of dialogue between Varys and little Martha). When Tyrion turns Varys in with "He betrayed you", he's not speaking of the conversations he had with Varys, he's referring to the attempt to poison Dany.

As for prophecies, they've pretty much abandoned any pretense of even remembering them. Cersei wasn't supposed to die under a bunch of rocks, but she did.