Jack took notice of Sam saying he wasn't afraid of someone, and assumed he hadn't meant to say it aloud. "Sam." Jack said, letting out a puff of air as he thought about how to word what he was going to say.
"You can talk to me. I didn't think you were okay, but I'm here for you." He stated, trying to remain on the good side of Sam's sanity.
As Jack spoke, Lucifer rolled his eyes and folding his arms over his chest. The angel then let out an exaggerated groan. "Come on, Jack. Say it already. You think Sam belongs in a white room. It's okay, I thought that, too! But he's really not crazy. I'm here, and you just can't see me." Lucifer explained, pulling at his own hair for a moment.
Jack took another look around the room, trying to pinpoint what Sam was seeing or hearing. But he couldn't seem to find anything. He wondered if Sam would pick up on his glancing around.