As I recall, as one of the buildings began to collapse in on itself, the top section (above the impact point of the airliner) did begin to heel over a bit, but it continued to fall straight down. It would be a violation of the laws of physics for it to have done otherwise. Buildings that tall, whatever the cause of their collapse, do not fall over sideways like felled trees. They collapse into their own footprint (give or take a scattering of debris when they hit the ground).

Don Firth

P. S. I'm amazed that this discussion is still going on.