You are correct, Mr. Todd, my mistake. Then tthe 3rd clack clack after the 3rd shot fired, the clack clack noise therefore was actually loading the 4th round from a final bolt action and that round the shooter stopped himself probably just an instant from pulling trigger having likely seen the some effect of the head shot.
Now this somewhat refutes Mr. Cakebread or causes an anomaly if Walt is correct about the 4th unfired rounds shell casing not having some mark on it from ejector similar I guess to whatever marks the other 3 ejected shells after firing the round had