One of the oddities of DEMIGODS & SEMIDEVILS is that although the Janitor Monk was able to effortlessly neutralize such Kiu Fung-level fighters as Siu Yeun San and Mo Yung Bok, he was injured to the point of having his ribs broken by Kiu Fung himself. Some have theorized that the Janitor Monk simply wanted to test the power of Kiu Fung's famed Hong Lung 18 (28) Palms. Maybe there was a more pragmatic and compassionate reason than that.
From Siu Yeun San and Mo Yung Bok's complete ineffectiveness against him, we can conclude that there was no way that even Kiu Fung could have hurt the Janitor Monk if the monk did not want to be hurt. In fact, if Kiu Fung were to launch his full powered Hong Lung 18 Palms against the Janitor Monk with the monk's defenses on, the reflected shock of Kiu Fung's own palm energy might badly hurt or injure Kiu Fung himself. Perhaps the Janitor Monk realized this, and out of compassion, absorbed the blow rather than deflected it to protect Kiu Fung from his own palm energy. The Janitor Monk probably knew that Kiu Fung was a hero and a good man, and did not want to kill him or critically injure him, and the only way to do that was to open himself to being injured by Kiu Fung's palm energy rather than send it back at Kiu Fung via his defense shield.