Garbage truck or street sweeper.

I had signed up for that theory, but the camera man was tracking the flashes, including knowing to skip the last two windows and go to the last window. Whomever was taking the video, knew the order of the flashes. I do know from experience that whenever demo is conducted with explosives, there is a crew whose job it is to document everything (video, seismic, etc.) associated with the shot (explosion). That crew is always in radio contact and knows the plan.

That said, I cannot imagine explosives being used for demo in the WH; the explosions would have blown the windows out; and there would be no way to keep it a secret.

So....jury is still out, IMO.