So, to repeat...we have a very-well documented mechanism for collapse that is backed by basic physics, and peer-reviewed technical science, and another that nobody will bother to answer a single question about.
Well first I never made the claim about thermite, although many experts have, but they don't count. If you want answers, ask them. Second, about you're claim that an explosive that is powerful enough to collapse a skyscraper wouldn't be silent, videos have shown explosive sounds, but again, they don't count. BTW, a firework is much less powerful then C4, but they're sound levels are about the same, perhaps louder in the case of fireworks.