But then it disintegrates while in the air, which again defies logic and the rules of physics. Concrete doesn't disintegrate on it's own.
The top half should have kept it's angular momentum and topple over, there was nothing stopping it. See the angle of the top 30 floors here:
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I think you're reading more into that picture. I see a ton of dust kicking up, but I disagree that the top of the south tower disintegrates while in the air.
Besides, building demolitions don't start with blowing up the top floors.