Castiel looked down, a bit taken aback by the familiar physicality the young woman was showing him. He thought to look into her eyes, to see who or what she was, but the other woman interrupted his focus.
He returned her stare evenly, face as devoid of emotion as ever. The ultimate "poker face", except when he did feel emotion is reflected in his features like light on glass.
She left in a very flamboyant fashion, much like demons enjoyed doing, flaunting her power while also concealing it. Every fiber in Castiel's angelic being wanted to follow her and question her, perhaps take a look at who she truly was.
But then there was the other part of him, that side that didn't always do the righteous thing, but always insisted his listen for the cause of "goodness".
He turned to the young lady who grasped his arm, straightening slightly. "I do not think she means well," he said finally, checking the other for any sign of distress other than her darkened mood. "Don't worry, I would not let her harm you."