At that moment, Wang Yuanbo mentioned the incident where Wu Anping arrested the two deputy directors, not to have Huang Feiming rescue them, but to shirk responsibility.
He wanted the higher-ups to know that it wasn't that he didn't want to solve the case or that he was slow to act, but that Wu Anping had detained his two deputy directors, preventing him from setting up a special task force and adjusting personnel in time. If the case remained unsolved, it wouldn't be his fault. If anyone was to blame, it would be Wu Anping for detaining those two, so he wouldn't have to take the blame.
Wang Yuanbo made this call precisely to shift the responsibility onto Wu Anping first. Even if the case wasn't solved later, he would bear less responsibility.