First and foremost, Li Fan was not acting out of embarrassment or anger, nor was he killing out of spite; he was merely testing new skills under various extreme conditions.
Regrettably, this time his attempt to use the sword flight technique on the membrane truly failed. It wasn't exactly a failure but rather ineffective. The Divine Teachings enforcer was a beat too slow, previously unable to escape even the top-tier evasion technique, Blood Shadow Divine Movement. However, this time, the antagonist managed to escape.
Of course, Li Fan had already calculated the influence of the surrounding chess game arrangement and defensive formations. He had also factored in lead time and conservatively chose to first eliminate the stronger Monarch Chijin. But as this was a new move, unrefined by battle, it could only be unexpectedly effective, yet not invincible or without counter.
