Fairly recently, ever since Castiel was pointed to a particular door and told, Go and learn from what you find, he's gotten a bit better at listening to his own instincts.

Right now, he's firmly pushing that new found skill aside.

This is the mission. He and Uriel need to show a united front. Get this done. Find out who is killing the angels.

And Castiel would prefer to do it while staying out of what humans term 'the doghouse'. So he keeps his distance from Dean, physically and otherwise.

"We have gathered a number of instruments you may find useful. I can show you."