That Liang Yong had betrayed his own sect twice, the latter time murdering his own sect leader while they were both in the process of leaving behind all their sect members, possibly to a certain death, to save their own lives. One could easily guess he had been waiting for a chance to kill the sect leader for a long time, but did not have the guts or capability to do it before then. Yang Kai was quite the fool to trust the man for a single second. Sure, it was his prerogative to do it, but in reality that decision caused untold suffering to millions of people and tarnished High Heaven Sect's name. I suppose this was as clear a sign as we have ever seen that Yang Kai is still very young and inexperienced in everything but adventuring and battles.