Echo leaving was Omega's first familiar loss in the series. She's lost her home and seen many clones die, but this is the first time that someone in her squad has left. She has no idea how to process this loss and doesn't understand when Hunter, Wrecker, and especially Tech don't react with the same confusion and anger that she does. They've all lost someone important to them, probably more times than they would like to keep count.
Omega doesn't see that, she sees a cold front, the product of abandonment.
Omega feels like Echo abandoned her, and Tech feels like Crosshair abandoned him.
That's why their conversation in episode 9 is so important. During the first season we, the viewers, see Tech blow up on Cross when they're escaping Kamino, but it is never mentioned again, whatever harbored resentment he may have is sidelined, and it is possible that Omega never saw how much it hurt him. And now with Echo leaving, she does see, that one mention of Crosshair, the pain in his eyes, she can now see that she is more like him that she thought, he's just used to being abandoned.
And now with recent episodes, in season 3, we'll have a chance to see another parallel. Omega never meant to abandon her family, she was taken and she'll most likely be brainwashed (or it will be attempted). Similarly Crosshair didn't have a choice when he was taken. He'll have to face the knowledge that Tech died coming to save him. That he died protecting Omega.
They'll both be a ressentful towards one another, rightfully. But in the end they'll realize that it was Tech's decision. That he sacrificed himself so that they could survive.
And Omega will realize that she's more like Crosshair than she thought. He's just used to being abandoned.