Speedo Cable through frame

[Chad215]

So, I'm stripping the frame down getting ready to paint, and I'm having a little trouble getting the speedo cable removed.
I can't tell how to remove it from the frame. It runs right behind the shock mount, and I see a nut on one side (outside frame), and what looks like some kind of (plastic?) clip on the inside of the frame. Turning the nut just rotates everything.
Just curious how this all comes apart before I start prying or gripping stuff and breaking things I would rather not break. Any advice here?