I think the only way he's ever going to split a single hair on Haegu's head, is the very last few drops of pity that she has for him. That's the fact that he's Mian's friend, the only reason why Haegu would hesitate or think twice. Otherwise, he'd be gone.
Hmmm.. he's already turned into a killing machine? Can he parry the queen of assassins? Looking forward to their match!