Lei Ao had once publicly professed his love for Sisi on the streets, to which Sisi responded, "The rules of the Hundred Clans stand here, let's see if you can defeat me first," and they fought right there on the street.
Although Lei Ao was acclaimed to be at the level of Eighth or Ninth Layer of the Mystical Gate, Sisi was more or less at the same standard. On the surface, they seemed evenly matched. However, when it came to the ingenuity of the moves, Lei Ao was simply no match for Sisi and was unequivocally defeated, ending up "looking for his teeth on the ground"—literally, as he actually got slapped and lost a tooth.
This incident was almost common knowledge in Xizhou Town, and Zhao Changhe had just arrived when Sisi told him about it.
Um, thinking back on it now, he wasn't sure if Sisi was in a rush to explain this to avoid suspicion? Perhaps that wasn't her intention, and one shouldn't read too much into it...