You know, if that was anyone but Ijin, going for a sword would be a pretty sure thing. Going up against a katana with a knife is no joke--for any normal person, their chances would be slim.
I'm just surprised this is still happening. You'd think by now the rumors would have gone all the way around the seamy parts of Seoul, so it'd be like--
Politician: "I want you to send a message to some punk schoolkid. Here's the picture."
Goon boss: "Oh, should be easy--wait, isn't that!--Ah, sir, I'm afraid we can't do that in this case. My apologies, please think of us next time. No, before you say anything, I'm well aware how much I and my organization owe you, and I know what you could do to harm us if you are displeased with us, but we can't do this. Both because this individual would hurt us far worse, and because it's the same way we can't break the knees of a typhoon. We could try, but it's not going to happen. You may find an organization willing to attempt this for you. They are fools, they will regret it, and so will you. I would advise you to try some other course of action."