Ep. 11 of Hospital Playlist Theory:
#Iksong

I think Songhwa and Ikjun really like each other since then (1999). But yeah, due to wrong timing they don't end up together. So in this ep. (11) when Ikjun already confessed his feeling to Songhwa(on the resto with colleagues)+

Songhwa feel fluttered at the same time she don't know what to react
(since their not teenagaer anymore unlike on the past) Ikjun is already a father and also because of their friendship. That's why I think why Songhwa chooses to go Sockho.
If she did'nt like Ikjun she could+

have said it (since she's so straightforward) but she chooses to leave without rejecting Ikjun(maybe she is having a hard time rejecting Ikjun because she also like him and it is hard when you rejecting your the one you love right?)+

So, Songhwa chooses to leave because she want to move on or have a distance with Ikjun to refresh her mind so after that she'll know what to answer in Ikjun's feelings for her.

There is so much problem with this two but please end up together