Bill, can't you restrain your contempt and cynicism sometimes? Please...
Some things I noticed:
- Around 17:20 a fighter plane - first time that I am aware of that one of the Otis birds show in a video. Between the two collapses. Hard to put a time stamp to that (and of course that moment may well not be the arrival of the CAP)
- At 19:41, the guy yells "OMG", signalling his becoming aware that the second collapse just commenced. So start of collapse was probably 19:39, or 19:40 if he reacted very quickly
- Collapse ist still underway at 19:55. Possibly a second or two beyond that. So collapse time (disregarding the delayed falling of the core) is at least 14 seconds, more likely 16 or 17 seconds. free-fall time from 95th story (where collapse began; about 360 meters up) would have been 8.6s, from roof (415m) about 9.2 seconds. So collapse was between 50% and 95% slower than free-fall.
- Collapse initiation is not accompanied by any major sound such as the sharp and insanely loud PENG from column-cutting high-explosives.
- 11:45: The people apparently were taken by surprise by the second hit; were not rolling film when the plane approached, but she obviously was scrambling to get it started, for she was filming just when the fireball emerged. Best explanation for this is she sensed the second plane coming in. Here speculation "military plane" can be excused: It was coming from the other side of the towers, and it is very difficult to identify a plane that is approaching you overhead. At 13:03 she explains to Bob: "It was a huuuge plane" - drawing out the u in "huge". So the identification "military" may be speculative and wrong, but they did see a HUGE plane coming, which prompted her to restart the camera..