you could also hear explosives going off (from what I've researched these buildings didn't have gas lines). The guy filming even mentions explosions. I have a good idea of what happened that day.
So, whats your point?
You hear loud bangs- several minutes after the building fell- is the only explanation that they were "explosives"?
if they are explosives are you insinuating that they are bombs?
Are bombs they only possible explanation for loud bangs during a catastrophic collapse of a building?