He couldn't save the adult Shin Yooseung, but in the failure there's at least one victory, which might even be significant: He drained plausibility from constellations that oppose his schemes. It means in the future they won't be able use plausibility as freely to mess with him. Probably the same goes for that intermediate Dokkaebi, who must have been forced to use some of his own as well. That's the big picture.