I'm glad Zacharia is gone. I understand the need to explain why "siding with the angels" is a bad idea, but the final episodes of the season are going to be a lot more interesting with charismatic characters representing both sides of the angel/devil debate. They need somebody with more charisma to play the "let's bring heaven to earth--the angels' way" argument.
That would be my assumption.
Castiel managed to "escape" wherever those Enochian symbols send the angels when Dean used it on him earlier in the episode. The only reason I'd imagine he'd have a harder time now is because he brought four others with him.
That would be my assumption.