Cruz has already stated, that the govt need not be shut down. Once the bill goes back to the house, they can pass individual bills funding individual agencies ... nothing needs to shut down at all. If the Senate votes against those bills, who is shutting down the govt?
If I had to guess, I believe Cruz has studied long and hard on the inner workings of both houses and how the system can be tweaked. I would expect that of a kid who could memorize the Constitution when he was still in high school.
Hearing McCain speak on radio, it is just plain embarrassing to listen to him. He sounds like an envious man ... he might have wanted to be the leader that Cruz is being.