He did as he was instructed, step by step.
There were many methods of hypnosis, and using magic was one of the simplest ways; however, since this method brutally interfered with the normal operation of the mind, it would inevitably leave traces. Especially when dealing with individuals who were already very vigilant, it might even backfire—like with Elma now.
Therefore, Long Yi had designed this more complex and slower hypnosis method for Elma. These traps ranged from simple to difficult, and any mistake would lead to failure, immediately teleporting the individual back to the entrance. Hence, if one wanted to pass all the traps, not a single step could be wrong.
Through this method, Long Yi allowed Elma to focus all his attention on the matters at hand, making him completely unable to realize that the Holy Temple he eventually breached was not actually a Holy Temple, but deep within his own mind!