After carefully taking a picture today when I rammed the dark slide back into the holder I pushed the negative back out the other side where it fluttered to the ground. Argh. Really, I was more afraid that someone saw me do that than I was mad about the lost negative.

Update
Apparently, my error was that I had inserted the negative into the dark slide slot rather than in the slot lower. It would have been unlikely that my shot would be in focus anyway.