This is proof of nothing except that by choosing clips from the hundreds of hours of news you can find a some people who heard explosive sounds.  All the rumours at the time of secondary devices have been discounted now and any structure of such immense mass when undergoing the stresses amd damage that lead to collapse will be emitting explosive noises.  It was common during the Blitz in WW2 for panics to be caused by secondary noises leading rescue workers to think other bombs were exploding