Actually, the real reason why Wang Shengyao wanted to stop Zhao Yu from reversing Feng Kuo's verdict was merely so that he could ingratiate himself with the Bureau Chief Hong Jianrong.
The case had been handled by Bureau Chief Hong personally back then. So, if Zhao Yu were to reverse the verdict, it would indicate that Bureau Chief Hong had neglected his duties, which would affect his future greatly. Hence, Wang Shengyao wanted to settle things on behalf of the bureau chief by stopping Zhao Yu.
"Hurry up! Release the people from the interrogation room!"
Wang Shengyao was clever. He knew that, under such circumstances, they couldn't act recklessly, but could only force Zhao Yu to launch an attack. Then, they'd have a reason to fight back.