Then you know that the ML only ever liked 'the girl from his past' as a little sister. It was she that was obsessed with him, that put the drugs in his drink (though she changed her mind and didn't give it to him - he took it from her and drank) and she that walked in front of the vehicle and got herself in the coma. That girl was in hospital and the other swimmer (the ML's ex-friend and rival) liked her and visited her often. The ML was told/assumed she went overseas. So yes there is a bit of a triangle of sorts. Well actually two triangles; the girls older brother likes the FL.
I think it is the last two episodes that really spell things out, or just the second last. It has been a while since I've seen it.
I quite like it too. Although it was a typical cdrama (everyone picks on one person who really only has one good friend and a love interest that believes in them), it was nice to see that it was a male getting picked on this time.
Hope that answered your question.
