Pieces of steel in cylinder??
It all happened when that hardened valve seat dropped out. Piston trying to smash that full circle hardened valve seat, sends the force down to the rod bearings and crank bearings and starts hammering them out of shape, while the pistons are trying to pound the valve seat chuncks into smaller and smaller pieces sending them into the other cylinders at the same time.
Hand grenade in the engine so to say.
Good photos of it all. Thanks