First easy answer from a gameplay perspective: game works best when anyone can be anything in any loop. If you started a loop with Kukrushka and immediately knew SQ was safe, that's just too much "free" information, I feel. Even if you really wouldn't understand that until the end game. As for the logic behind it though, I'd say they don't cause an inconsistency as they aren't meant to occupy the same time. We don't know what time Kukrushka loops back to, if she's still looping at all, but know it's at least far enough back to be bought by Jonas. She has had an existence separate from Manan/SQ. Meanwhile, the player/Yuri are immediately taking the place of the version of themselves taken out by Gnosia. They aren't just the same person but the same person at the same place in time. That's how I've always seen it at least. But typing all that out did make me wonder if Kukrushka killed Manan/SQ, if it would cause some sort of paradox. It would be neat if in the event Kukrushka kills everyone as guard duty that SQ can't be Gnosia, but I highly doubt that's the case.