Adult Fear version of batshit scary. Imagine you have the happiest little baby girl. She seems so happy all the time. She either laughs or sleeps. Wait, what? It means she has a brain tumour? She is just having seizures? And operation on baby this young is extremely risky?
The situation when the transplant doctor tries to force another doctor to pronounce one patient brain-dead. He's actually alive and he could hear everything. (He responded to verbal command.) From the charater's perspective.. he must have felt awful and absolutely desperate.