Just because shots were heard above them doesn’t necessarily mean they came from the sixth floor.
True!...... But I doubt that Williams heard any shots from above them. He incorporated the two shots from above, AFTER he had heard that they had found two spent shells near the 6th floor, SE corner window. If he had heard shots from somewhere above why didn't he tell Jarman and Norman....and why is he seen looking down toward the triple underpass in Dilliard's photo ? Williams didn't hear any shots from above!