Amadeus knew exactly what Ariel was doing and he didn't try and pull his hands away. There was a part of him that even in his anger knew he'd be thankful for it later and if anyone understood how prone he was to lash out with his magic when he was angered it was Ariel. So instead he just tightened his hold in return letting his lover know he understood and wasn't going to fight him on it.
That part of the Elder Tremere that was all Hunger, Anger, and Beast right now could only look down at Rhys in disgust because of how weak the fledgling was being. It made the other lingering part of him glad for Ariel holding him back as weakness like that was never a good thing to show a pissed off predator even if one was begging forgiveness.
A muscle in Amadeus's jaw twitched, making it clear he was clenching teeth as he appraised the younger Tremere. There was a part buried deep inside right now that knew he himself was not completely infallible where Rhys was concerned. He had likely been too lax on the boy. Too much freedom. But this wasn't like with his own childe who he had kept by his side at all times. Time and distance made it hard to keep a tighter leash. Maybe Rhys would be better off turned over to the chantry.
These were not decisions to be made right now though. Instead, he gave a nod of his head. "Later we'll be discussing some new ground rules. And also later you can thank Ariel for neither him or I killing you."