"You are my family too"
That is so important let me tell you why:
Ever since Octavia began training with Indra, ever since she became the warrior she is, she sees people different. You can even say she used to it even before that. But with Indra's knowledge, with how she helped her not only fight but to know how to read your enemy, she has been very cautious of knowing who are her enemys and who are her friends.
Octavia is smart, yes there are moments when the show made us doubt that, with all the bloodreina stuff or going crazy over lincoln, but wit bloodreina that was her way too keep anyone together, too not let anyone die who wasn't necessary and she lost her mind because of that. With lincoln it was the same thing, the love of her life had died, it was her way to cope.
I'm not saying that she is right and should be pardoned by every mistake she made, but she was barely a child when she was confined, and a teenager who didn't know anything apart of what her brother told her. So of course she is going to be a little different. And in that way assessing people and what will they do survive became her specialty.
Now the "you are my family too". Bellamy knew that Echo weakness was her loyalty. So it's only logical that Octavia knew that as well, because if Bellamy "The Heart" Blake knew how to judge someone weakness, a warrior like Octavia that explores the weakness knew too. Let's not forget that they fought against each other, that Echo did everything for Azgeida and Octavia knew that.
Everybody knows that Echo is a great ally to have at your side. She needed Echo's loyalty if she was going to survive. Echo is fragile, all her life she's been following someone, Octavia knew she needed a link, or she would go crazy and probably kill everyone in her path like we saw her do.
So yeah, it is a bit weird hearing Octavia tell her, Echo, the person she hates and told all kind of awful story to Hope, that she is her family too. However, it is a brilliant move, one she must have made to survive
