Not just noises but voices, look at where Norman and Jarman were and reportedly they were hanging out the windows to talk to each other, so if Williams was directly above in the sniper's nest then he would have been closer to Norman than Jarman was.
JohnM
No mention of hearing voices......but maybe walking or window movement.
Mr. BALL. Why did you stop on the fifth floor?
Mr. WILLIAMS. To see if there was anyone there.
Mr. BALL. Did you know there was anyone there before you started down?
Mr. WILLIAMS. Well,
I thought I heard somebody walking, the windows moving or something. I said maybe someone is down there, I said to myself. And I just went on down.
Mr. BALL. Did you find anybody there?
Mr. WILLIAMS. As I remember, when I was walking up, I think Harold Norman and James Jarman as I remember, they was down facing the Elm Street on the fifth floor, as I remember.
As he was directly above at the time at an open window, not at the 3rd or 4th set of windows from the east behind closed windows.....certainly possible.