My guess is he was already a crap teacher but was "good enough", but then he messed up a students cultivation after when it was time for student selection all of them were terrified. No students, no score.
Hooh, it would seem that we will now see the first time he uses his cheat or whatever, at least I assume so. How else would he guide a student better? The only other way would probably be by luck or an underhanded trick.
Shame? Thick-skinned? What a joke! In the era that Zhang Xuan lived in, in order to become famous, some celebrities went to the extent of doing all kinds of shameful deeds. They did everything that one could think of, be it nude photos or fake news, without the slightest sense of shame. He scored zero for his Teacher Qualification Examination, but it was nothing in comparison to the deeds of those people! Very true
Transcendent