It was the first time that Ryu had laid his head down to rest in several years. This wasn't the first time Ryu had entered a deep sleep after a long while of wakefulness, but the circumstances around this time were entirely different.
Setting aside the fact that Ryu's Focus Qi was almost entirely drained, the changes to Ryu's cultivation were most definitely the largest, ignoring his Dao for the moment. The problem wasn't just that Ryu had broken through to a new room, because this also wasn't the first time that had happened, obviously. The problem was that Ryu's body chemistry and biology had completely changed.
Accommodating a new Spiritual Foundation sounded simple enough, until you remembered just how important the structure and pathways of one's Meridians and Meridians Nodes were. You couldn't just randomly form a new attachment and expect everything to work the same.