Kitahara had feelings for Nagaoka, Kurosawa for Takagawa... no wonder Kitahara ordered the "hit" then.
At least Kurosawa doesn't see Takagawa as she changed her appearance and matched Nagaoka attitude too, it's good that her image in his head starting to disappear so he may not hold his unrequited love now, but still feel regret he's not by her.
Damn, Kurosawa lost also the only person who always reached out to him, even if he scoffed him off...
Feels bad man...