I don’t know what cruz is doing, but if they do this, it will end the GOP.
Cruz is trying to win enough delegates to play a role in deciding who the nominee is, and what dopes like Ryan and Romney don't understand is Cruz doesn't need their help to get that done.
The obvious play would be for the #1 & #2 vote getters to join forces, although if Trump gets close enough he could join up with a lessor candidate such as Kasich if that combination puts him over the top in delegate count.
Only in the event of a Mexican standoff does Romney/Ryan stand a chance.