Hearing Nie Yan's nonchalant tone, his father really wanted to teach this brat a good lesson. Someone like Bayonet was a national treasure, a rare find that money couldn't buy. If such a person were to leave due to Nie Yan's neglect, it would be their loss.
His father had a change of heart regarding Bayonet. The skills Bayonet demonstrated were clearly honed in the military. If such a person were willing to work as a bodyguard, he could ensure Nie Yan's safety, and his father would be willing to spend any amount of money for such peace of mind.
In the military, strength was highly esteemed, and having it could earn one respect from others. Once it was clear that Bayonet wasn't there to cause trouble, his father, with a military background, respected Bayonet even more.
His father said to Nie Yan, "No matter the cost, we must retain him. I've transferred three billion to you. If that's not enough, ask for more." His father was really splurging to recruit Bayonet.