The problem is the manner in which he describes the scene. It's supposed to sound bleak and desperate, but it comes off as fucking hilarious. His tryhard, faux-poetic verbiage like "sunset found her" is paired with blunt phrases like "shitting brown water," which creates a silly juxtaposition. "The more she drank the more she shat, but the more she shat, the thirstier she grew" sounds out-of-place because it's sing-songy, like a pastiche of a children's storybook. And just try saying the sentence, "Every stool was looser than the one before, and smelled fouler," without laughing.