The moment Ren Tianxing heard about this, he became silent too. Given his pride, there were very few people whom he admired and even though Mo Wuji was an outer disciple with a rather low aptitude, Ren Tianxing enjoyed interacting with him. Furthermore, Mo Wuji never looked down on himself even though he was only an outer disciple.
Ren Tianxing was willing to befriend Mo Wuji, give up on searching for the earth fire in the Lost Sky Ruins, accompany him back to the sect and even gift him a self-disguising spiritual item precisely because he truly admired a person like Mo Wuji.
Now that he realised that Mo Wuji might have fallen, he would naturally be feeling slightly dejected. It definitely wasn’t easy for a cultivator to meet a true friend in this world.