"You're fucking exhausting, you know that? Everything is zero or a hundred with you," Bentley spit, running an agitated hand violently through his hair. "No wonder your sister needed breaks from you. I bet she couldn't breathe. I bet you never let her breathe."

First of all, fuck you, Bentley. This is some toxic, vile stuff to be saying to someone who lost a sister and quite clearly never got over it. What a horrid thing to say to someone who clearly didn't want to talk and has been trying to distance herself the entire conversation. Not only that, there was tension when they were younger that I am assuming he never apologized for or acknowledged.

Secondly, this does make me think that perhaps Bentley has some connection to Mirae or perhaps Mirae's death. The "no wonder your sister needed breaks from you" sounds like he has talked to Mirae before or noticed something between the sisters. This part was also interesting:

When Soojin failed to respond, he continued, his breath hot and venomous in her ear. "I feel bad for your dad. It must be hard for him that the wrong daughter survived."

This feels so specific and pointed, but possibly not at Soojin? It feels a bit like a projection, especially since he randomly brought it up. Either he went through the same thing with his own family, or he's somehow connected to her death and should have died instead of her. I'm not sure. This might be far-fetched, but this reaction is so wild and sounds like self-hate.