Second
If others were watching, they would feel Ryu's cultivation increasing by leaps and bounds.
From the 1st Extinction, to the 2nd, to the 3rd, the 6th, the 9th, and somehow even increasing beyond.
Ryu couldn't feel these changes too subtly because he was entirely focused on making sure that he didn't lose himself in the Chaos Plane. Although he had his Dao to rely upon as an anchor, if he wasn't cautious, he could still very easily lose his life, something he was obviously unwilling to allow to happen.
However, even if he was aware, he wouldn't be very surprised.
The continuous reformation and destruction of his Inheritances, although happening without his knowledge or acknowledgment, could have been considered a process of Extinction. The difference was that the process was far smoother and safer, likely facilitated by his Meridians themselves.