If Barnett is certain that he is guarding the front entrance door by 3 min post shots, and Mrs Reid is certain that Oswald entered the rear door of the 2nd floor office at 2 min post shots walked "slowly", and that Oswald was only wearing a T shirt
then Oswald would not exit by front door of the 2nd floor office until 2 min 30 sec, having to travel about 90 ft at 3 ft/sec pace (slow)
Oswald would then have to travel 100 ft in the outer hallway to RETURN to the 2nd floor lunchroom to get his brown shirt which he defacto must have taken off after being seen by Baker and Truly, with at least a long sleeve shirt on, any possibly a jacket also.
Then Oswald must go back down the hallway again, yet another 115 ft to reach the front stairs, or else use the rear staircase, then trek acroos 140 ft of 1st floor to reach front door. There is also about 20 ft to travel from the bottom stair of the front staircase thru the lobby, to reach the front doors.
Total distance = 235 ft. plus an 18 step staircase with a 4ft mid landing
Subtracting 10 sec for going down front staircase leaves Oswald about 25 sec at best to travel 235 ft,
235ft/25sec= 9.4 ft/sec sustained average speed.
This is without adding the extra seconds to have slowed to a stop, to get his brown shirt and jacket, nor adds slowing down caused by 2 doors entering from hallway to lunchroom ,nor the repetition going thru those 2 doors and then a 3rd door just before getting to the staircase.
If you add those delays in, its closer to 10 ft/sec, which is flat out maximum sprinting the ENTIRE distance.
Using the rear stair is even more distance, approx 140 ft at least, so total distance would be 255 ft.
This is, imo, highly improbable and it also is in stark contrast to Oswalds previous slow movement and apparent lack of urgency when seen by Mrs Reid. Plus, its not even necessary to have used the front door, if there is a West side entrance which may not have been yet secured by 3 min post shots and is close enough to the back stair, to use, if Oswald had seen that the rear dock door of the annex roofed part of the dock was the route he might have tried first.
No one saw Oswald doing this 235 ft Olympic speed sprinting, nor saw him exit the front door, the rear door, OR the West door, so the answer must be some LAX actual securing of the doors , despite Barnetts statement or else, Oswald met Mrs Reid BEFORE he met Baker and Truly, but that is a question of the Couch Film time vs the Wiegman film and ive already mentioned the anamoly there between Weigmans film STOPPED at 13-15 secs post shots, but this being captured in the Couch film at the 8 sec mark in Couch film thus not possible if Couch film did not begin until 24 sec post shots.
Perhaps there is an explanation by Weigman that he remained standing frozen after stopping his 1st sequence of fliming, camera off, not doing anything for another 17 secs after filming the 2 people (the Hesters) and then he decides to turn around and notices the Newmans laying on the ground. This event captured by Couch at 32 sec post shots, 8 seconds into Couch film which began at 24 sec post shots