The demon grinned, then, stretching Castor's lip up above his incisor.
"You're a good man, Liam," it said, quietly. "Find out what happened on that flight, I need to know."
Just don't go digging too deep, it thought. Or we'll have ourselves a problem.
The demon rolled Castor's neck, cracking it to hide its discomfort. Most of its kind were prone to obsession in one form or another, it tended to be what drove them. Even among the Fallen, they all followed inflated characteristics, repetitive heuristics that defined their persona. It didn't mean they were incapable of doing anything else, but it was part of their psyche that they were driven to exaggerate whatever their particular drive was, often to the exclusion of other traits.
That was why the humans were so beloved, of course. Their flexibility, their freedom of choice. It was something that, for all their rebellion, Hell's demons often lacked. Sabnock wasn't an infiltrator, it was a builder, a siege-captain who had raised the walls of Pandaemonium and commanded legions. It was comfortable in the role assigned to it in the capacity that it was sent here to break defenses, but the subterfuge and skullduggery, the mimicry of the human scientist, Castor, wasn't something it enjoyed.
It was making it restless, violent, prone to mistakes, and it knew it. And Castor's constant screaming inside its head wasn't helping.
The man was clever, and he was unrelenting. More than once, it'd caught his finger tapping against his thigh, beating out a tattoo in Morse code spelling out 'Help Me,' that had been muted in its efficacy by the bandages. More than once, it'd had to expend an effort of will to suppress the man, resulting in Castor's eyes staring off into space. He was making it lose patience, and the veneer of respect it'd had for its host was wearing thin, along with its patience.
The wariness of the exorcist, too, was something to watch. It could tell that Roe wasn't completely buying what it was selling, and it resolved to 'check in' occasionally. Perhaps when the man was sleeping.
"Understood, and if things get a little hairy out there..." it said, giving a comradely smile to Liam. "Permission or not, I'll be there, if you need me."
It shucked Castor's wrist clear of the shirt cuff, and glanced at its watch.
"Right, well, I think they'll be along shortly to take me down to the MRI," it said. "Thanks for coming, Liam. It means a lot."