The Inner Divergence training regime was less elaborate than the Outer Convergence training session, but it was even more difficult.
Rui found it quite hard to fundamentally change how he deals with incoming attacks; this training required him to get rid of some of his muscle memory and built new muscle memory.
Furthermore, every time he failed, he would effectively be taking an attack head-on without any defense whatsoever. Since Squire Fare did not allow him to use Acute Edge or Elastic Shift during the training regime.
By the time a few hours passed and his first training session with Inner Divergence ended, Rui had completely lose count of the number of healing potions he had consumed in that one session alone.
('Thank fucking god the Academy doesn't charge the students for every potion we consume, otherwise I would be bankrupted to hell and back. Even becoming a Martial Master would not free me of the sheer amount of debt!')