Rong Fei didn't stop Nian Bing's actions because, before the competition, Rong Qinwang had told him not to interfere with anything that Nian Bing did during the contest.
Mu Rong stopped in his tracks, looking at Nian Bing in surprise. By this point, Mu Jing had closed her eyes and her sweet little face revealed a tranquil aura. Bathed in light, her previously pale face gradually flushed with a hint of red. Fifth-rank brightness healing magic continuously flowed through Mu Jing's body. Nian Bing withdrew the Holy Radiance Knife, and his other hand extended to touch Mu Jing's forehead where the icy aura emerged. This time, it wasn't cold ice but rather ice transformed into soft water with the fire's help. Following the light, it started revolving around Mu Jing's body.
Mu Jing opened her eyes, her pupil full of astonishment, "It seems my domain has recovered, how did it happen so quickly?"