Xia Fei initially planned to leave on that day, but Shadowless and Craneshadow seemed interested in his proposal to reform the Assassin Sect; hence, they convinced him to stay for the rest of the day. The three discussed the details throughout the night. They only let him go early the next morning.
The truth was, Xia Fei's ideas were not even that brilliant. He was simply suggesting the Assassin Sect to be more considerate with their disciples. Huge organizations like the Adjudicator Union and small factions like the Assassin Sect both consisted of humans, so if they could solve the conflict between humans, they would have no trouble resolving the bigger problems.