The 'white smoke' could just be water vapor that condensed inside the exhaust and when the turbine kicked on the heat vaporized the condensation. Would have to know more about local temp/ humidity to be certain and I mean temp/ humidity INSIDE the stadium. As for the helicopter after it lifted off, the wind pattern in that stadium had a significant effect on how that helicopter performed. Wind currents inside the stadium can cause turbulence. I believe the pilot was closer to one end than desirable and 'backed up' (helicopters can do that) before applying power and ascending. This gave the pilot more room to maneuver. I watched the other video (pb) and for the helicopter to enter that kind of spin it normally means the tail rotor has lost power. It can no longer counteract the rotation of the main rotor. Mechanical problems do happen and quite often at the worst time. Not saying it was mechanical failure though. I'm wondering if there was something the pilots didn't see that collided with the tail rotor? Although I didn't see any sparks in the previous video. There would have been a shower of sparks if it had hit something or something struck it. There was no smoke from the tail rotor either. It looks like the tail rotor just lost power. How? I have no idea. All speculation on my part.
Then respect the Constitution and the oath you took to support it.