I dunno, I think it's thematically more appropriate leaving him there. It was his choice to stay behind, and he's the one with the gun. And coming back would have gone against the choice of telling him that it is over. It also doesn't fit with the earlier decision about the positive of being with Leo vs the negative of being in Echo.
Yeah, that makes sense. I guess it's just my own nature to not want to leave a friend behind in danger. Being angary with them and braking up with them is one thing, leaving them in mental distress and in danger is another thing to me! I especially wouldn't want to lose a friend I'd known for my whole life, in real life I have! Just a bit passionate about this since I can relate to it very well. Also in the story I'm kinda not impressed with Kudzu....