Bing Wuqing's suggestion was quite tempting. The Soul Seizing Palace had colluded with the Central Prefecture, and had managed to work out Su Yu's true identity. He had desired to kill them for a long time. Su Yu would be happy to see them completely eliminated, so had no obvious reason to reject Bing Wuqing's suggestion.
However, as Bing Wuxin's face appeared in his mind, Su Yu said coldly, "I will reject your offer." Even though he didn't know why Bing Wuqing was trying to thwart Bing Wuxin, nor understood the grudge between them, he didn't like to betray people.
There was now a great possibility that he would end up missing the Glittering Jewel Wonderland. This would especially be the case once Bing Wuqing announced Su Yu's true identity. Once people learned that Su Yu was an enemy of the Central Prefecture's King, no faction would be willing to face the anger of the Central Prefecture's King, and help him.