Hi Tim - just looked at mine. I've got the SD card cover open as I speak. The card hasn't popped out and the display is stable.

If the card itself is loose, it means that the spring catch which holds the card in place - inside the recorder is probably faulty. The 'door' is merely a cover, and appears to have no place in keeping the card contained.

If that is the problem, sounds like it might have to be a new recorder...