The video presents Inori (though she looks more like Mana, Shu’s sister) falling down and meeting a blue-haired version of her. There’s a pixiv fanart out there which has Akane and Shinya as the pink-haired and blue-haired Inori respectively. And seeing that, you get the analogy that this song is all about their relationship.
And given by the recent events in the series, the lyrics really tell that Akane wants to help Shinya, who is falling out of his sense of duty. Given Shinya’s selfish and destructive reason for what he had done recently, he failed to realize that there’s one person who wants to help him and that’s Akane. Yeah, this sort of sounds like a romantic relationship. This is a very sad song and it fits perfectly to this series.