OK so here's my take on the song ‘You In Me’ and the MV
Reading the lyrics, it feels like the what metaphorically ‘died’ was the relationship. The girls keep asking “why don’t you say anything to me, I’m sorry, you’re the only one I love, need you in my life, etc.” and in the MV they’re the ones that are taking care of the boys, looking at them, touching them, initiating. J.Seph and BM rarely look the girls in the eyes, and for the most part they’re sitting stationary in one place, not responding to Jiwoo and Somin’s actions. They’re rapping about how they feel half-dead, how it’s hard to breath, how the relationship is basically beyond saving.
Couple that with the “APEGO” sign that flashed in the beginning, which means attachment, it seems like the song is about a failing relationship that neither person is willing to end, one due to passiveness and one due to their unhealthy attachment to their SO.
Also near the end, you see Somin realises that something’s wrong and she kind of has a breakdown, but both she and Jiwoo decide to stay in their very one-sided relationship and the song ends with “you’ll be mine forever.” idk which counterpart I feel more sorry for, the bf who’s being held hostage in a relationship he doesn’t want or the gf who’s putting in all the effort and getting nothing back.