BRW left the 6th floor via elevator to 5th floor approx 12:24 and went to join Norman and Jarman who had arrived at 12:24 to their respective windows.
So the gunman on 6th saw BRW leave the floor and he placed the box within 1 minute on the SW window ledge. This is plausible if the gunman is within 70 ft of the SW window.
The shooter after firing 3 shots with a rifle that can fire 3 shots in about 4 secs as Harold Norman heard them spaced per his film recorded demonstration of such spacing in his “Boom Clack Clack” sequence.
The shooter therefore was NOT using the MC rifle that was found on the 6th floor at 1:22 by Weizmann and Boone.
The shooter had to have used the east elevator to by pass Mrs Dorothy Garner on the 4th floor
This scenario however, cannot be possible if Baker/Truly upon reaching the 5th floor saw the WEST elevator was gone and could see the East elevator was still on 5 th floor , to which they claim to have then taken the east elevator to the rooftop, and bypassed 6th floor without Baker even checking the floor.
This seems suspiciously like CYA and therefore imo the EAST elevator was the one that was gone and then Jack Dougherty was selected by WC to be using the west elevator which is questionable since Eddie Piper does not confirm having spoken or seen Jack Dougherty.
The 6th floor shooter has to get off the floor and down and out of the TSBD building which makes the staircase not probable due to the presence of Dorothy Garner near the staircase on 4th floor as early as 40 secs post shots.
Other alternatives:
1. The shooter was dressed like a plain clothes officer , possibly WAS a legitimate officer who hid himself somehow on 7th floor and then came down later when there was much confused traffic going up and down the stairs.
2. The shooter used a vent shaft on the 6th floor to get himself down to the top of the passenger elevator on 4th floor thru the elevator shaft. Then into the elevator and took it to the ground floor. ( Armstrong theory)
3. The shooter has an accomplice holding the the East elevator locked on 6th floor after 12:25 just after BRW had left the 6th floor to join up with Norman/Jarman on 5th floor. The shooter ran with his rifle to the East elevator in 25 secs after last shot fired and he waa delivered to 2nd floor landing by 50 secs post shots. The accomplice then returned east elevator to the 5th floor by 70 secs post shots. Jack Dougherty becomes a possible candidate to be the accomplice in this hypothetical scenario.
I hope I’ve answered Mr. Devils advocate question