This "staring into the distance, glazed over look", is it taught in their school? All my personal experiences engaging Witnesses is that they all do the same thing when faced with undeniable fact. It must be a condition of Cognitive Dissonance. Their brain cannot compute so it shuts down as a means to protect itself.
Honestly it seems a waste of time to discuss anything with these people. They just don't know how to listen and think for themselves. The GB has done a number on the Witnesses that's for sure.
I talk to elders and show them stuff and they all do the same thing. They cannot address a single question. They just sit there, eyes glazed over like a jelly donut unable to do anything. Then they tell you you're satanic or something stupid.