Agree that Rowland saw Williams and gunman. Was my original conclusion in 2014. Also Williams left SN unexpectedly.....chicken left behind. The puzzle is the movement of the west elevator after Jarman and Norman leave the gates shut on fifth. I suppose Dougherty already on sixth can call it from the sixth if he is already there. Take from sixth to fifth, then down to first while Baker and Truly ascend....or he just takes to sixth, then down.
Jarman and Norman take the west elevator up to 5th
Williams takes east elevator down to fifth.
At this point both elevators are on 5th as are Jarman, Norman and Williams.
Dougherty is on 6th
The problem is that this is the situation when Truly and Baker are stood looking up at the elevators.
Truly is supposed to have tried to call the west elevator but it didn't come so he and Baker hit the stairs.
The only way it works is if Truly is somehow involved.
It's actually part of his "role" to slow the first law enforcement in.
He hollers up the elevator shaft announcing his arrival, pretends to call the elevator but it doesn't come, then hits the stairs.
Either Dougherty calls the west elevator to the 6th floor and takes it down as Baker and Truly are ascending or...
When Baker and Truly get to the 5th the west elevator is on 6th floor. After they go to roof Dougherty takes the elevator down to first, then back up to 5th floor in time to be seen on 5th by Truly as he and Baker descend to the 1st floor from the 7th
Why does Dougherty need to make this quick trip from 6th to 1st to 5th?
I think it's because he has to drop off the "real" rifle in the west shipping section of the TSBD where it is picked up by Shelley/Lovelady and put in Shelley's car parked just outside the west door. While they are doing that Dougherty returns to the 5th floor to carry on as normal.
All of this speculation is predicated on Truly being in on it and not really calling the west elevator when he and Baker are at the bottom of the elevators.