Bab 175: No Warning

Before the effect of the silver needle wore off, the trio agreed to knock Scarred Man out and dumped him on the ninth floor where Lily would be able to spot him easily.

At first, Shen Nianzu had indeed planned to kill Scarred Man since he was Lily's teammate. Even though the man was crass, brazen and impulsive, he ought to possess one real skill or two for Lily to accept the man by her side. Shen Nianzu did not like to leave such a large risk factor that could potentially come back to bite him in the ass. 

However, he promptly changed his mind upon noticing the signs of alienation on Scarred Man. 

In the end, Shen Nianzu decided to keep him alive not only because he would be a ticking time bomb by Lily's side, but also because he realized that the man's alienation seemed to be different from the others he had encountered so far. Hence, he chose to observe the man a little longer.