Just a thought concerning Baker's comment about seeing someone on the third or fourth floor:
" As we reached the third or fourth floor I saw a man walking away from the stairway. I called to the man and he turned around and came back toward me." (Affidavit on day of the assassination)
If Dorothy Garner's statement to Barry Ernest has any credence the fourth floor can be ruled out as she would have been in the area it was supposed to have happened.
This leaves the third floor:
The stairs Baker and Truly were ascending are in the top left-hand corner. They would have come up the stairs to the left (north to south) turned left and left again in a tight enclosed area and then come to the bottom of the stairs going up (east to west). It would be at this point Baker would have seen the man walking away from him.
This is just a personal opinion but the space between where Baker would be standing and the elevators seems too small for the encounter with Oswald to have happened in. When Baker says he called out to the man who turned around and walked back towards him I get the impression there was quite a bit of distance between them. If it happened on the third floor the man walking away from the stairs can only have been a few feet away from Baker, maybe five to ten feet.
I'm not saying it can't have happened that way, it just doesn't 'feel' right to me. Why would the man have to walk back towards him if they were so close?
Just a thought.