Zhou Tian, upon seeing the rabbit's actions, not only did not step in to stop it, but also didn't think of pursuing it after the rabbit had gotten far away.
Firstly, Zhou Tian was busy dealing with the fox at the time, thinking it better to break one finger than to injure ten, he preferred to first kill the fox before considering keeping them all. Secondly, the rabbit cultivated the Lightning Law, and although Zhou Tian could surpass both of their speeds in a short time using his Time Ability, he really couldn't maintain the use of the Time Ability for long durations, and thus couldn't match the rabbit's speed.