#partial lung collapse

Because now, even after Whumpee is saved, their lungs are scared and the damage is done. What exactly is the damage? Partially collapsed lungs, partial atelectasis to be specific, where certain areas do not inflate anymore and thus Whumpee will never have a full breath.

…that something that had so taken over how they breathed every breath had no distinctive moment of initiation, no before and after, no harsh red line distinguishing.

Maybe it was because they were so adept at brushing away discomfort that they pushed through the initial trauma. Or, it was what the doctor said now, that maybe one trauma led to the slow partial collapses of sections of their lungs, like tired dominos, inevitably falling, each area filling with air one last time before refusing to inflate again, tired and spent.