The power-down described by Scott Forbes was probably when the second hit ruse was set-up. Plane parts planted, fuel bomb planted, on the unoccupied floor 83.
The angle of attack of the second hit was carefully designed so it would be AWAY from where the first plane hit. News cameras not in on the plot would primarily by focused on the north face of the north tower, where the hit was. The second hit officially came from the south, so there was less chance of random cameras getting it. Only news people in the know, also helicopters would be set-up to view the south approaching hit.
Dark flitting shapes in distant footage probably show the missile.
Close-up footage is all fake.