Woo-Moon dude shouldn't be so easily provoked by small fries if he fancies himself an unparalleled master. Other masters won't take him seriously, which will make it harder to get them on his side.
Other than that, this makes him hiding his identity previously totally pointless. Sure, plans can change, but this is a work of fiction, so plans changing would look better connected to major changes in other things, such as the enemy behavior. Now the only change was that the MC thought, while riding his tiger in leisure, that maybe, after all, not hiding his identity would serve his purposes better. So, it was really just Woo-Moon reevaluating his own decision from mere weeks ago (at max). You could call it indecision if you wanted to be really critical.