It is canceled by the energy of the red giant rushing towards the gas giant.
Canceled kinetically, that is. Obviously the energy is not destroyed. You have been told this about 5 or 6 different ways now. Frankly, I'm amazed by the creativity of the HZ inhabitants.
Also obviously, the star that began this discussion found a way to get to its incredible speed; so it can be done somehow. That it was not done by a coordinated attack of relativisticly traveling gas giants should not be a disappointment.