Structural engineer explains what he saw in condo collapse footage

A concrete building like that should NOT get pulverized like that, if the lover pillars got compromised the upper stages shouldnt be, but as we all saw, the whole building turned into ashes, I think the concrete used was of substandard quality, even the Gazan concrete after getting bombed with a couple of 2000 pound bombs dont get pulverized like that, I never seen anything like this before, a building doesnt drop on itself with the speed of gravity as if there were no support whatsoever from upper stages, each floor should have resisted to some degree slowing down the collapse but this building just dropped in seconds, I say something with the concrete was the issue throughout the whole building and not just the ground floors or the garage, they should look into the other buildings that construction company built to see in what condition the concrete is in because those buildings could be in danger too.