“Some vermicular, primordial instinct”

…there it was, reflected back at him: the inside of his belly, etched in blocks and lines of black against the fluoroscope screen’s sickly calcium-white, suspended in a void that detached it from anything and everything. Organs, tubes and bones quivered and oscillated against each other awkwardly, like animals — reptiles, molluscs, nether-dwelling creatures — who, crammed together in a space too small for them, bristle with aggression towards one another yet understand, through some vermicular, primordial instinct, that the survival of each depends on that of its unwanted neighbours.