Eunji had planned to spend the rest of the night with her girlfriend. But since life seems to want her to always deal with problems and more problems, she couldn't have that happiness.
So she just had to give up on the idea of being with her girlfriend and sent a short message explaining the whole situation.
Something like: honey, unfortunately I need to take care of someone, even though I don't want to do it, but my idiot brother is threatening her with drugs and money and she's most likely on the verge of a breakdown and only God knows what she's capable of doing. And what I'm capable of doing if that happens. I love you, I miss you.
Well, it wasn't as detailed as that, but that was the spirit.
Eunji just went on autopilot, since she was interested in headaches, avoid taking Nari home.
Nari being in a controlled environment would avoid many future problems and Eunji could keep a close eye on her sister.
