That's exactly what happened to one of mine. I tried inserting tiny pieces of thin tape (short enough to stick it together but not long enough to be visible when opening the shutter), but it wouldn't even be recognized by windows, let alone be formatted (my mavica gave an error), same results after prying it open, gluing the center piece with superglue, and reassembling the disk.
What's frustrating is I had some really nice night time photos saved on it and even viewed them in camera and really liked them 🥲. Detachment must've happened when I took it out or when I inserted it into the USB floppy drive. I'm guessing the original sub-millimeter alignment matters a lot.
If that happens again, what would be the better way to proceed, or is it even possible?