Unable to sleep in his own right, Cas had taken to frequenting the observation deck when he wasn't observing the alien behavior or spending his time with Anna or Dean. They did not fear any of them. Not the Doctor. Certainly not him or Anna. Perhaps not even Lucifer, though Cas wasn't about to question that. That would entail drawing closer to Lucifer and that was the last thing he wished to do.
He smoked, he wandered the halls. When he returned to his room, he meticulously cleaned his weapons, but seeing as they were of very little practical use, they were mainly glorified bludgeoning devices. Though that was not to say he was above using them as such. The fact that he wished to fight the aliens was not a secret and he didn't care if they knew it or not.
Elpis had at least given him renewed hope. He was no longer as angry as he'd once been. And with Anna by his side, he did at least feel as though it didn't matter whether he was home or not.
Yet when the other being crossed his path, he very nearly reached for his gun out of habit. "You are unable to sleep?" he asked.