Xi Chenxiao fell into deep thought when he heard Su Jin's question. Xi Tian had sent someone to investigate the matter; it's possible that something fell through the cracks. Moreover, the way Bai Xue did things was completely different from what he remembered about the young girl. Although she was very young back then, he could tell that their styles were very different.
After Xi Chenxiao ordered his men to detain Bai Xue, he gave Xi Tian a chance to redeem himself. Xi Tian was ordered to investigate Bai Xue's background thoroughly to find out if she was really the girl from back then. If Xi Tian failed again, Xi Chenxiao would not be sympathetic; he would make Xi Tian wish that he was dead. Xi Tian rushed out immediately when he received the order, afraid that Xi Chenxiao would castrate him.