Why doesn't it make sense? Franky exists doesn't he? Why is it so hard to believe that there would be some other cyborg around? I don't see how Kumo being a cyborg and having a devil fruit ability would be considered dues ex machina. Even Sanji almost broke his leg a couple of chapters ago by trying to kick his head. If I'd consider anything being dues ex machina it would be Kuma leaving without killing anyone with some dumb deal done with Zoro.