The narrator recovers from hypothermia,
Were you a Norwegian fisherman or Inuit hunter, both of whom frequently work gloveless in the cold, your chilled hands would open their surface capillaries periodically to allow surges of warm blood to pass into them and maintain their flexibility. This phenomenon, known as the hunter's response, can elevate a 35-degree skin temperature to 50 degrees within seven or eight minutes.
Other human adaptations to the cold are more mysterious. Tibetan Buddhist monks can raise the skin temperature of their hands and feet by 15 degrees through meditation. Australian aborigines, who once slept on the ground, unclothed, on near-freezing nights, would slip into a light hypothermic state, suppressing shivering until the rising sun rewarmed them.
...you surface, as if from deep under water. A warm tide seems to be flooding your midsection. Focusing your eyes down there with difficulty, you see tubes running into you, their heat mingling with your abdomen's depthless cold like a churned-up river. You follow the tubes to the bag that hangs suspended beneath the electric light.
And with a lurch that would be a sob if you could make a sound, you begin to understand: The bag contains all that you had so nearly lost. These people huddled around you have brought you sunlight and warmth, things you once so cavalierly dismissed as constant, available, yours, summoned by the simple twisting of a knob or tossing on of a layer.
But in the hours since you last believed that, you've traveled to a place where there is no sun. You've seen that in the infinite reaches of the universe, heat is as glorious and ephemeral as the light of the stars. Heat exists only where matter exists, where particles can vibrate and jump. In the infinite winter of space, heat is tiny; it is the cold that is huge.