It was a relieve that Yanlin didn't die if not it would have brought up a complicated situation that Si Ning might be able to solve but he won't be able to do a thing about the pain those close to Yanlin would feel, especially her mother Yanyu and Si Nan.
Si Ning was exhausted, it was mentally draining checking to make sure Yanlin was breathing but since the danger was over he only wanted to eat then rest, and for the first time he was looking forward to getting to his bed at the Jasmine Palace.