Engineer fag here. Your premise is impossible. Not unlikely, not improbable but straight up fucking impossible because of first year engineering statics.
Any freshman engineering student knows I am right. You know what held up the towers? Every floor below. Know what could have happened? A slow pancake of a few floors with a center column still standing. Still impossible but more believable. But know what? Fuck that and explain building 7. Go away, you glow.
Scared much? You don't need to get very far into statics to understand this.
Who is sliding who here?
Nice of you to prove my point.