The problem with the hypothesis presented in the video is that "implosions" in the demolition sense of the word don't create a vacuum. Any sort of bombs or explosive charges would in fact have created higher pressure.
Or rather I should say, any sort of conventional bombs. Clearly what must have been used here are implosives. At last report, implosives were being developed by the Soviets at a facility in Minsk around the mid 1980s. According to documents recovered from the aftermath of the Soviet collapse, the project was supposed to have been abandoned by 1988. But perhaps it was instead merely handed off to others?
The most powerful type of implosive is the G/S or Gas-to-Solid type, but those have proven tricky to manufacture in more than minute qualities, so most field demonstrations so far have been of the less powerful but more stable G-L or Gas-to-Liquid types. The action of a G/L implosive can be seen as analogous to the detonation of a liquid explosive, in reverse. The implosive is deployed in gaseous form contained within a balloon-like plastic envelope ranging from one to several thousand cubic meters in volume, depending on the application. To facilitate the reaction, the inner surface of the plastic envelope has an invisibly thin coating of the necessary catalyst, whose composition (like that of the gas) is of course top secret. When the implosive is triggered, the catalyst causes the gas in the bag to turn into a liquid, reducing its volume by several thousandfold. This causes the bag to shrink to a tiny fraction of its former volume. This change in volume is extremely rapid. In fact, for so-called "high implosives" the collapse is faster than the speed of sound, a true "tonation" (the opposite of a detonation).
Obviously, the effect of an implosive is the reverse of that of an explosive. Instead of a pressure wave blasting outward, the implosive creates a vacuum or, more precisely, a rarefaction wave which causes all nearby materials to rush inward toward the center of the volume formerly occupied by the implosive gas. In a test in 1988, the tonation of a G/L implosive inside the fuselage of a decomissioned Antonov An-124 Ruslan (on the ground) caused the fuselage to crush lengthwise in a series of accordian-like folds. The collapse was complete in 0.23 seconds and left the enormous aircraft shortened to less than 12 meters from nose to tail.
Setting multiple implosives off across several dozen floors of a large building would obviously present serious practical problems, especially if the building were on fire. (A smoke screen, however, might plausibly be used as cover for the deployment, and be mistaken for a fire.) Multiple gas envelopes would surely be needed, and the tonation of all the devices would have had to have been precisely synchronized to create the necessary vacuum. It's up to others now to determine how this was achieved and, more important, why it was so important that wtc7 collapse in 4.5 seconds instead of, say, 10 seconds that such a massive effort be undertaken. We should all be asking: what was the hurry?
I hope these facts help to shed some light on this mystery.
Respectfully,
Myriad