It reveals that "combustible materials" had been stored in the stairwell and the self-closing mechanism on the fire door to the flat in which the young jockeys died was not working properly.
All over the rich world, there are parents who leave the child-proof lids off medicines because they find them so fiddly, and office workers so irritated by self-closing fire doors that they prop them open.
Everything proceeds in orderly, if grim, fashion, until one day the mob sends Joe's future self (Mr. Willis) to be executed ("closing the loop") and Young Joe allows Old Joe to escape.