In the beginning, Old Jiang didn't give Han Fei the Great Thousand Pill Sutra, but the Spirit Gathering Scripture. That was right! With Han Fei's personality, how could he study alchemy every day? He couldn't even have enough time for fighting.
With the Spirit Gathering Scripture as the catalyst and Old Han's guidance, he could supplement it with the Ocean Book. In fact, Han Fei didn't lack methods to set up arrays. He just needed time to familiarize himself with them.
Once Han Fei had enough time to consolidate and use these arrays, he was confident that his achievements in arrays would be at least as good as Old Jiang's. It would be easy for him to kill law-enforcers with arrays.
In the past, Old Jiang would always set up some arrays in the Twisted Forest for Han Fei to break. Now it was a real battle, because Han Fei's choice just now gave the other party time to repair the array.
Once the array was activated, the terror of a spirit gatherer was shown.