Amon had warned Tuang Yin in advance about his intention, so Tuang Yin closed her eyes while looking down when the Flashbang Grenade exploded. She wasn't blinded, but she was close enough to be deafened by the noise.
Amon was the same, but they had prepared to act once the explosion was over. The two jumped and ran up the building on opposite sides.
Amon threw his flying knives while climbing. The senior up there couldn't see or hear, but he was alert enough to take action when he realized the potential danger. His weapon, which was a long staff, spun around to protect himself. The staff was spun using martial arts. It created a defensive bubble that deflected Amon's flying knives.