Yeah so this episode showed that E was fully aware that Clarke was one of the most important people in Bellamy’s life. Maybe Bellamy didn’t let her or anyone see the full blown breakdown he had over her death last season and just how deep that connection was and how much he relied on it, but E knows full well that he loves her.
We can take 2 things from this. First, that in s5 she must’ve had some idea what she was doing when she tried to kill Clarke. But to E, betrayal warrants death. Even after all that time on the ring, she doesn’t know anything of substance about Bellamy. She doesn’t know that Bellamy wouldn’t ever want Clarke dead, even if she did betray them. Flash forward to now, she genuinely doesn’t know or understand what Bellamy would do in this situation.
And second, is that she completely hates that. Bellamy is all she has. He’s her leader. He represents direction and meaning and was the in to the only “family” she’s ever had. And yet she doesn’t know him at all. Maybe they can be casual together, and laugh together. She knows he’s a good fighter, and hates algae. She knows the things that their little bubble allowed her to know. But the deep parts? What he does in a crisis? How he feels, where he finds his meaning? She has no idea. Unfortunately for her, that’s the part of Bellamy that Clarke and only Clarke really knows. And yeah she’s kind of bitter about that. Bellamy is the biggest thing in her life, and yet Clarke gets a piece of him that she doesn’t. Now her purpose for living is dead, and she’s being slapped in the face with the fact that so much of what she was holding onto was fragile and ultimately meaningless. What does she do now?