Well, even if she had his best interest that was way out of line. U see, authors tend to not really measure the impact of some decisions with the characters just to reach their goal with the plot. Putting Sung-Hwa in this spot make her look really bad unnecessarily and also contradicts how her character should be seen by the readers. Someone that takes so many rash decisions wouldnt be able to achieve so much success on her company as she did. Its almost like the successful woman from the company stayed there.