At night they fight constantly. They judo-flip each other headfirst into the plywood floor of the tent. They strong-arm their buddies into headlocks and punch bruises into each other’s ribs. They lie in wait for one another in the shadows and leap out swinging Ka-Bar knives, flecking their buddies’ rib cages with little nicks from the knife tips, or dragging their blades lightly across a victim’s throat, playfully simulating a clean kill. They do it to keep each other in shape; they do it for fun; they do it to establish dominance.
