I honestly don't fully agree with Souma's assessment of Hanabi here. I understand him thinking this way after years of abuse, but he seems to see her as someone who wants everything to be about her, wants to be the "tragic heroine", wants to be the center of everything. I do think she's so used to overestimating herself that she tends to see her side of things as bigger than they really are, but I don't think she really wants to be the center of anything. It makes it sound like she thinks she'll win sympathy or something, but I'm pretty sure she was already too broken to seek that when the camp incident was over. It's just that, since she'd always viewed herself as more important and others as weaker and generally inferior, now she has trouble weighing how much her actions impact the world, or at least the people most important to her in this world. In short, she doesn't want or believe she deserves to be the center of attention for good or ill anymore, but she is still somewhat deluded about her own weight and power. Might be a big part of why she locked herself in her room even after the suspension ended, because in her mind she'd committed an unforgivable sin and didn't deserve to move on, rather than having simply wrecked one relationship with a person who has more than healed and left it mostly behind him. So, since she's still convinced that her actions have terrible consequences and that she has the power to crush someone she can't bear to hurt again, she's wiling to do anything to stop it.
This last bit might really be good for her in this regard. She's been shown that her actions have enough weight to wreck relationships that matter to her. Now she'll learn that her actions don't have so much weight that they'll crush others' relationships. She shouldn't stick around him because she has hurt him, but she doesn't have to lock herself away unable to even die out of fear of hurting him again. She can go on with her life, and who knows, maybe once she's managed to grow out of her own preconceptions she may be able to stand before him seriously, earnestly, and once more apologize for her idiocy. It will likely take years, but someday she may be able to reach a point where she can talk to him as an equal, maybe even become a proper friend.