Core is stuck inside case

Picked up a G4 Cube at a yard sale a few weeks ago. Computer’s “core” is stuck inside the clear plastic case, will not come out when I use the built-in latching handle. I recall seeing (a while back) that the core can become stuck if the Optical Drive is installed wrong, but I don’t know if that’s the situation here. Anyone experience this? Any recommendations for getting the core unstuck (that don’t involve destroying the machine)??