As everyone went along with their own thing after the near-death experience, Leo and David, who were the only ones among everyone to witness the power of the two mutated birds, continued to ponder over their weakness.
In the end, both of them grew restless and started to exercise. Yes, exercise.
It was Leo who started it first.
After eating what had been given to him by Anna and talking with his daughter while petting her to sleep, he got restless when he had no activity to do, and the nagging thoughts that he was wasting his time when he should be getting strong kept hitting him.
In the end, after Anna offered to put Yuki in the car so she could sleep more comfortably, he went to a location near the car and started swinging it with a practised stance. He was training.
It only took a short while for David to also realise what Leo was actually doing. It interested him, and he decided to partake as well to vent the frustrations in his heart.