There he must, despite the anguish devouring his brain, present a face approximating the one that is associated with ordinary events and companionship. He must try to utter small talk, and be responsive to questions, and knowingly nod and frown and, God help him, even smile. But it is a fierce trial attempting to speak a few simple words.
Your eye will no longer linger on the light, it will no longer trace constellations. You'll care only about the darkness and you'll watch it for hours, for days, maybe even for years, trying in vain to believe you're some kind of indispensable, universe-appointed sentinel, as if just by looking you could actually keep it all at bay.