It could almost be said that although Zhou Tian had various methods of applying the Time Rule, at that time his control ability over the finer aspects of the rules was merely at a beginner's level. Even though Zhou Tian's Time Rule could play a significant role when fighting opponents of the same level, when facing those who specialized in the various rules, especially the cultivation of the Time Rule, Zhou Tian's insufficient control meant that his opponent might only need to exert a fraction of their strength to disrupt Zhou Tian's rule ability.
Therefore, if Zhou Tian didn't have the foundation of the Human Emperor's immortal body at that time, he genuinely would not have been qualified to combat Pan Shi. Given this situation, to Zhou Tian, Pan Shi naturally became something like a natural 'treasure trove'.
While Zhou Tian was not weaker than Pan Shi in combat power, Pan Shi far surpassed Zhou Tian by more than just a little in the cultivation of rules.