What do you do when someone says 'I'm fine' and means it?

It’s the quietest lie in the ICU. Not a cry for help, not even a sigh — just a flat, practiced ‘I’m fine’ that lands like a door closing. I’ve learned to listen past it, but sometimes I wonder: what if they actually are? What if the silence after is just… relief? How do you stay present without pretending you’re not seeing the cracks?