A big shift in direction might put him on guard. It’ll be easiest to work with the current topic.
“So, are these anti-magic cages only an issue for mages like you? Or is there something that makes them dangerous to the ‘ungifted’, like me?”
“The cell is merely made of objects with high resistance to ether. Trectite bars with silver coating, significant amounts of moonwood amongst the walls. They pose no danger if handled by mundane means.” The voice pauses. “Well, I suppose in theory, someone could attempt to cast a lot of spells despite the countermeasures. In such a case, it’s possible that even a nonmagical disruption could release the ether stored up by those materials, with unpredictable results.”
You’ve never heard of trectite or moonwood before. You wonder if it’s worth asking about them, or if you’d be better off trying to guide the explanation somewhere else.
There were no suggestions for this update. I went for a coin flip on whether or not to ask him what the materials were, though the prompt was probably more intended for suggestions about their origins.