You knew very well who Hwang In Ho was and where he was when Hwang Jun Ho lost information about his brother as he fell into the ocean. He only remembers when he was shot in the shoulder. When Hwang Jun Ho realized that you knew about his brother, he decided to find you. He's the police, and he may well be following you, in his opinion. When you left the store and turned into an alley, you saw Jun Ho pointing a gun at you. He was spying on you.

Jun Ho: "Tell me quickly where you found information about my brother and where he is located."

His voice was stern and authoritative, but not very aggressive. He wanted to be polite.