Rean had been healing cultivators who came back from missions or got injured because of other reasons. The elder who took care of the building was very pleased too. After all, Rean's Light Element control helped save a lot of pills and expenses. Rean didn't mind either since it was his duty days, not to mention that he will get 300 sect points when it finishes in two weeks.
In fact, Rean was quite happy with this chance. That's because he had been thinking about his own control of Light Element and how to use it recently.
Rean was inside a room, healing another disciple. However, he wasn't simply sending Light Element inside that disciple's body as always. Instead, he was controlling it in a different way to achieve another effect. If that disciple tried to run now, he would definitely be much faster due to the Light Element running through his body.