Look at the southeast corner (the one nearest to this sentence).
Notice how far ahead the plumes are on the east side is compared with the south side, despite the very short distance between them.
This is how the adjacent buildings to the WTC complex is "spared". The top falls neatly into WTC-4. See for instance how little damage there is to the pedestrian bridge right next to WTC-2.
Nice isolated plumes down along the corner - and only here.
As on all other demolition videos of both towers, the corners is blowed out in the same fashion. Of course, as they are the strongest part of the outer wall.
Some time after the first demolition wave, you can see relatively large chunks shooting out from the core.
