At 10:10 in the video below we see Fritz as he walks into the area containing the rifle. The other side of the boxes is swarming with law enforcement officers. As Fritz moves across we see the area that the mystery man is stood in. This area is also swarming with officers (highlighted in red):
There are other moments in the video when we see this area crowded by officers milling about. The area in question is between the stairs and the elevators and would have been kept clear for freedom of movement.
Is it Lovelady stood on a box after taking his shirt off?
Why would he be stood on a box? In his HSCA interview, Lovelady repeats that he stayed by the elevator while he was on the sixth floor (it is interesting that Lovelady, Shelley and Dougherty all testify that they were present on the sixth floor around the time the rifle discovery).
Why did he take his shirt off, the room is full of men wearing full suits. many wearing hats. They don't seem to be affected by the heat?
It seems to me it's equally possible that we are looking at a tall man. Not an extraordinarily tall man. Just someone well over six feet tall.
It seems to me it's equally possible it's someone who didn't remove any clothes, who was just wearing what they were wearing.
This doesn't require a lot of unnecessary assumptions that seem unsupported by what evidence little is available.
What is clear is that the mystery man is not a police officer. He can only be an employee of the TSBD. And not an office worker.
This leaves two realistic choices - it is either Lovelady on a box wearing different clothes or it's the very tall Jack Dougherty wearing his own clothes.
I don't know if James Hackerott is around anymore but it would be great if he could use his "stacking" method on the short piece of video footage in which the mystery man appears.