Sui Xiong originally did not want to interfere with the battle between Ray and Steele. In fact, he hadn't noticed it at all.
After Steele fell asleep, her heaven-sent ability was activated so that she snuck into Ray's dream like a Night Witch. This process was quiet and made no noise, so Sui Xiong didn't notice it because he was concentrated on his research.
But then these two were fighting fiercely and noisily in Ray's dream. They were almost demolished the house. For Sui Xiong, who was good at soul perception, their fighting was almost like a fly—no, a hundred flies—buzzing noisily beside his ears.