Spoiler!!!
Chi-hwan doesn't turn Soo-in into a vampire at least not in the next chapter Soo-in gets VERY upset at Chi-hwan for suggesting it and starts crying and for the first time tries to push him away when Chi-hwan tries to comfort him.
Although they have not realized their feelings yet I think for Chi-hwan seeing Soo-in get sick scared him knowing he might die if he gets too ill so I think he ended up jumping the gun a bit and thus was thinking of turning Soo-in into a vampire to prevent that as a way of keeping him safe.
He seems to realize his error though when Soo-in gets upset and hugs him and apologizes all in all I do think he does care for Soo-in but he probably has never loved anyone before so he is all new to this and tends to things into extremes as measures for Soo-in's safety.
Anyway I am glad he doesn't as it would seem a bit too soon for Soo-in to make such a major life-changing decision I have a feeling they may make this choice later on in the series but for the sake of storytelling I am glad they are not going to do it quite yet as Soo-in needs time to think and prepare if this is something he wants to do.
woahhhh why we goin so fuckin fast?? woahhhhh(⊙…⊙ )