The video "America 911" (Camera Planet, c 2001) has footage shot at Ground Zero on the afternoon of 9/11, and sometime before 4:15, a firefighter being interviewed points to Building 7 and notes that the building was already leaning and was going to collapse:
"You see where the white smoke is, you see the thing leaning like this? It's definitely going to come down. There's no way to stop it. 'Cause you have to go up in there to put it out and it's already... the structural integrity is not there in the building. It's tough, this is terrific, you know we're getting hit with just about everything today, this is beyond..."
Just thought I'd add that into the mix...