The way the building collapsed and came down appears to be from multiple points on different levels throughout the building.. In other words, like the supports underneath had been removed on multiple floors for it to collapse that way it did.
I watched videos YEARS AGO of exactly that, Every level when it was coming down, you could see the blast just before the upper part of the structure got to that level. Only folks with blinders on wouldn't see that.or NOT want to see that. I think that is the case.......