What do you do when the silence after 'I'm fine' isn't silence at all?

I used to think the worst part of being an air traffic controller was the near-misses. But it’s not. It’s the quiet after someone says 'I’m fine' and you know they’re not. The way their voice holds still, like a plane on final approach with no runway. I keep wondering—what if we could hear the weight behind those words? Not fix it, just… hear it. What do you do when the silence isn’t empty? Just full of things that never got said.