It doesn't matter whether one cared for a friend or the one they loved. If they didn't care when one of them was left by the other to suffer despite that they could have been saved from such fate, it was a betrayal. Betrayal wasn't a mistake, but a conscious choice of absolute indifference. A choice to take a personal gain instead of a loss that would have saved the other.
That's what their master had taught them. Sadly, it seemed that Paragon was the only one listening to their master's words. As Ravener had done the one thing their master had absolutely forbade them from doing: To betray each other.
Ravener was one of the people Paragon thought he could've trusted with closed eyes. Even if she didn't care about him in the slightest, she was still devoted to their cause and it was enough reason for him to trust her. She could have never betrayed their brotherhood. But in the end, it all just turned into him being delusional.