Ahh...since there was no other girl featured at all through out the entire vid, perhaps the crest-fallen look on the PA's face when he discovered his 'boss' sharing a moment with the girl is understandable...he was in a relationship with his PA!
Observation: No, the camera guy and the assitant ain't gay. The photo assistant likes the girl (note the way the PA looked at her at the beginning when she is apolagising after she got in the way)
Well, I guess the lyrics is fitting for the end of the story. The girl will "curse him" for the sacrifice he made, her wish is not for him to lose his vision. And also for giving her up and handing her over to the photo assistant. She still loves him
He still loves her, but he feels that he is responsible and is angry with himself (scene where he sit in the darkroom and his espression in the scenes after that) Due to his love and guilt he sacrificed his vision. Perhaps due to his guilt or handicap, he cannot be with her (Korean Man ego is bigger than japanese ah~) and hand her over to his assistant who he knows like her as well so that someone would take care of her.