WTC1 77W-75N Ejection Begins Before Collapse Initiation
By detecting motion by subtraction, over-pressurization can be seen on
the 77th floor as early as the collapse initiation sequence 20 floors
above.
High quality Achimspok study of ejection:
https://www.youtube.com/v/acTcwA_YHuA?version=3
The moment when the 77th floor ejection first becomes visible is shown below:
It is important to know that the 77th fl MER HVAC system only services floors xx to 91 as shown:
