The governing constraint is the stretcher, not the headcount. A hospital bed or trolley is considerably longer than any passenger cabin is deep, and it must enter the cabin, sit level, and be withdrawn at the destination floor — generally with an attendant at the head, another alongside, and frequently a drip stand, monitor or portable equipment travelling with the patient.
This produces a cabin geometry that would never be specified for passenger use: comparatively long and narrow, entered through a substantially wider opening. Where this is specified incorrectly, the consequence is not reduced comfort but an installation that cannot perform its clinical function.