For some reason it just occurred to me that the FBI Hosty note about Oswald being “out front watching the P. Parade” could mean that Oswald had said he was out in the front LOBBY looking out at the parade thru those big clear glass walls.
This would be consistent with an FBI account of Carolyn Arnold having stated she had seen Oswald in the front entrance LOBBY approx 12:25 when she looked back towards the front doors of TSBD. ( she saw him through the glass wall).
This would also be consistent with Oswald on film saying he was IN the building when asked where he was at the time of the shooting.
So now it all works out quite well that Oswald had been sitting in the 2nd floor lunchroom eating lunch when Carolyn Arnold saw him there at 12:15.
Then after Carolyn left to go outside with her friend Virgie Rachley , Oswald decided he should return to the Domino room and finish his lunch there ( probably thinking Carolyn might say something to Mrs Reid and he would get in trouble if he stayed in the 2nd floor lunchroom.)
So at about 12:23 Harold Norman and James Jarman , returned to the rear door of TSBD at the loading dock and they bypassed the Domino room , and they were seen by Oswald going to the rear elevators. N&J , however, did not see Oswald because they were looking 180 degrees the opposite direction at the elevator shaft.
So Oswald saw and probably heard something said by Norman or Jarmin about the JFK limo about to arrive, which prompted Oswald to leave the Domino room and go to the front lobby and look “out at the parade” at around 12:25. He was then seen standing by the plate glass wall, in the lobby, by Carolyn Arnold looking back at the TSBD entrance.
Now, after the shots fired and Oswald saw Baker running towards the front entrance, Oswald crossed the lobby and went up the front staircase, and then down the outer hallway of 2nd floor and into the 2nd floor lunchroom.
Why did Oswajd do that? Probably because that was where he had left his jacket and maybe had his keys in the jacket also. He needed those before he could go outside to see what the commotion was about.
So this times out remarkably well that Oswald had just entered the 2nd floor lunchroom at about 80-85 secs by using the outer hallway.
And the opening and closing of the 2nd inner door by Oswald when he went thru vestibule to enter the lunchroom, caused the light streaming thru that 2x2’ window of the outer door, to flicker which caught the eye of Baker as he arrived to the 2nd floor landing. This prompted Bsjer to shift over to look thru the window and that’s when he saw Oswald walking away.
It all works out now that Oswald remained IN the TSBD lobby ( and he was unseen by Piper in the lobby because there was solid brick wall that blocked LOS to Oswald.from Pipers position at the south side TSBD window where Piper was looking out.
This would explain how Lovelady and Shelley would not have seen Oswald whether they arrived to the rear elevators either by the west side door of TSBD or if they came thru the front lobby 15-20 secs ahead of Truly and Baker.