I asked him about this switch down to my left. He claimed he didn't know what it was for, but I suspect it might be a self-ejector switch for nosy passengers who can't keep their hands off important airplane stuff.
From Walt Fricke--
Your comment on the "ejector switch" reminded me of the time I took a rider in my CJ-6 (Chinese yak)….  I told him “Just don’t touch anything back there and we will do just fine”…he insisted that he wanted to know because…"what would he do if something happened to you"…?     I said.."Well…then you can touch anything you want!"
Walter L. Fricke
Veterans Airlift Command