I recon you'd do worse damage hitting the machine hard. I haven't come across this one before but the first thing I would try is get some very thin but semi rigid plastic, like the stuff that is the window on toy packaging (Mini-Obi has his first birthday, hence why it sprung to mind!) First try it flat or maybe use a ruler to fold a tiny 'barb on the edge and gently try and fish the disk out. Looking online may tell you where the sensitive bit (lens) of the drive is so you can try and avoid that. Good luck.