Rui's emotions fluctuated immensely throughout the entire battle. When Senior Ceeran and the matriarch of the K'ulnen Tribe began showing their true strength at the start fight, he had been shocked by the true capabilities of both Martial Artists. Not only was their raw prowess incredible, but their techniques were very interesting as well.
The matriarch employed the same principles that rockets did to achieve extreme acceleration. Except unlike rockets, she could apply that speed in all avenues in combat while rockets accelerated in linear motion exclusively.
This allowed her to dart across the battlefield at blinding speeds. Frankly, if not for the giant infernos she left behind with every step, Rui would have had absolutely no chance of tracing her movements and trajectories.