Doctors, soldiers, and mothers encounter it routinely; I had, any number of times. Unable to respond to an immediate emergency while clouded by fatigue, the mind simply withdraws a little, separating itself fastidiously from the body's overwhelming self-centered needs. From this clinical distance, it can direct things, bypassing emotions, pain, and tiredness, making necessary decisions, cold-bloodedly overruling the mindless body's needs for food, water, sleep, love, grief, pushing it past its fail-safe points.