It would be a, not sure what to call it, but a way to “connect” to TLJ making a connection about ‘the’ third lesson.
Of course the lessons back in TLJ was to disuade Rey from training as a Jedi, or “prove” the Jedi were wrong, but it would be a fun “twist” he plays on the lack of the third lesson (since Rey left) from the last movie and “converts it” to an actual “Jedi good/right” lesson.
Kinda would be a fun play on the whole lessons thing from the last movie.
Yeah. This was basically my thinking on including a “Lesson Three”.