There is the possibility that Oswald could have been hiding at the NE corner of the 6th floor near an east facing window where he theoretically had LOS to Norman and Jarman walking at ground level along the Houston st. side of TSBD. Oswald therefore upon hearing them on 5th floor below him after he placed a box on the SE window ledge at approx 12.24:45, knew Norman and Jarman had to have bypassed the Domino room to re-enter TSBD.
Oswald might have been trying to look out this east facing window to see if the motorcade had yet entered Dealey plaza , while Oswald was waiting for BRW to leave the 6th floor.
Of course this is theoretically not probable if Oswald escaped via staircases, because of Mrs Garner on the 4th floor.
However , an elevator escape is possible if Oswald had an accomplice who could take Oswald via the East elevator from 6th floor to the 2nd floor landing by 50 sec post shots, thus bypassing Garner who had no LOS from her position by a west window near the staircase. The accomplice then returned the east elevator to the 5th floor by 70 secs post shots where it appeared stationary when Truly and Baker supposedly arrived at that time to the.rear elevator shaft. The West elevator was then taken down by either the accomplice or Jack Dougherty after Truly and Baker began their ascent up the staircases.
However, for the elevator escape scenario to be possible requires that BRW must leave the SE window by 12:23:30 which in turn requires Norman and Jarman to leave from the front side of TSBD EXACTLY at 1:22 so that they get to 5th floor windows BEFORE BRW joined them.
If Walt’s timeline is the more accurate, then it’s several minutes PAST 1:22 (after the radio heard) that Norman and Jarman started their return , passing the Domino room at 12:25 and not until 12:27 approx getting to their 5th floor windows.
If Walt’s timeline , then not only is it impossible for Oswald to place the box on the window ledge by 12:25., it’s impossible for ANY gunman to have done so unless BRW was the one who placed the box, which makes no sense unless BRW is helping the shooter.
The only way imo to resolve this dilemma would be to refute the supposedly confirmed time stamp of the Bronson film starting at 12:25.