Earlier before the fight in the corridor started, Seoyeon's as aware of the difference in power between her and the axe witch. She had seen how large his figure was and how strong he could lift a large broken wall with a single hand before throwing it toward her which she avoided only to create a large dent on the wall, she learned that using an honest fighting method would only cost her limbs or worse lives.
She then recalled Jung Hwa and his personality where he would use trick slyly. Taking him as his inspiration, she decided to create traps using the left over strings she found in one of the room that was used to hang lights and use it below, on the floor of the corridor.
She used the advantage of having a larger and taller opponents to divert his focus from looking below. As she had used string, it was also hard to be seen which added another advantage for her.
