Blank
Ryu's mind was entirely blank.
Sleep wasn't something that he had experienced for years, there was simply no need for it. Even during his games with Selheira, there were enough breaks in between that his Focus Qi never truly hit rock bottom.
Ryu had never experienced what it meant to run out of Focus Qi. It could be said that a large part of that reason was because of the prayer mat, but beyond that, he had never been forced to use so many talents and fuse them in such a way at the same time. In addition, maybe the greatest reason was the Unbalanace Mantra which constantly forced him to deconstruct the world he was used to and reconstruct it in a completely novel way.
Either way, the fundamental truth of it all was that it had taken a great deal out of Ryu. However, he also knew that he didn't have much time to allow himself to fully reset. If he did, he might as well give his life up now.