RE: Bernoulli vs Newton
As with the helicopter on the scale, there was just enough residual thrust in the first condition to allow the vehicle to creep forward.
The amount of power required for the vehicle to move when the motor was reversed was much less than the full power needed for the first condition, which in essence resembles that of a turbo-jet using reversed thrust to stop.
But as a propulsive scheme, as way too many people wish to use for pushing a sailboat, it's as impractical as anything could be.