While Feng Ao Si was contemplating life, Nan Hua was looking at Feng Ao Kuai's hand. Even though Feng Ao Kuai was acting as if there was nothing difficult in his attempt to defeat Feng Ao Si just now, she knew that it was not the case.
Feng Ao Kuai was doing whatever he could to make sure that no one noticed that his right hand was actually trembling. It was because he had no other choice but to block Feng Ao Si's attack head on due to their difference in body speed.
Feng Ao Si had grown much faster and stronger while Feng Ao Kuai focused most of his training to improve his legs and arms in order to be able to shoot arrows faster. He didn't really focus on speed, which was why he tried to dodge with the minimum distance as much as possible.
If the fight had continued, he would surely lose because his strength couldn't match Feng Ao Si.