You had a lot of time to figure out what you can actually do with Wind powers, while you were struggling fruitlessly to--anyway, it turns out they're not JUST for making really sharp knives and flying around. You can also cut things apart from each other in a way that's not physical.
As for Shirh, you could have cut her loose a long time ago, but in that place it would have been cruel. Now that she's made you a murderer you wish you had. This shit isn't what being a warrior is about. It's about protecting your comrades, like you tried to do for her! It's about national security and looking really cool in front of everyone!!
So you cut her out of you, but she's still there. You think you could cut that invisible cord too, the one stretching longer as you fly the fuck away from her. But she's right. You are a nation of two, and guarding her is all that kept you going all this time. You're never going to see any of your friends again, clearly--
You stop midair, above a vast junkheap piled onto an endless shore. Where are you, actually?? And how did Zevvie get here???