The 'secret appraisal technique' was a rather troublesome skill, and Song Shuhang had to pay a heavy price every time he wanted to use it. In addition, once in a while, it would even activate on its own...
However, he had ultimately managed to grasp the secret appraisal technique a little, and along with his comprehension of the technique getting better and better, there was bound to be a day when he would completely master it.
As such, Song Shuhang was willing to keep this 'secret appraisal technique' with him even if it was somewhat troublesome.
On the other hand, this 'nucleus' that had suddenly appeared in his Heart Aperture was completely not under his control, and it was very similar to a parasitic organism. Therefore, Song Shuhang felt that it was better to get rid of it as soon as possible. One day, if he found a way to control this 'nucleus', he would then put it back inside his body. Of course, the prerequisite was that Senior Medicine Master could dig it out first.
