Panasonic DMR-E55 has disc stuck inside - won't open

I put what was apparently a bad DVD into my Panasonic DMR-E55. The DVR tried to read the disc, but after 3 "ticks" (display showed / / / ), the process restarted, and basically went into a loop,

The problem is that in order to eject the disc, the DVR seems to want to read the disc first, which it obviously can't do,, so I'm stuck in limbo.

The last time I had this issue, I held down the Stop Button and Volume Up (or Channel Up - I forget), but I tried that this time and all that did was give me the message "LOCK". Then it went back to the "reading" loop,

I finally just unplugged the machine, as I didn't think it was good to leave it just trying to read the disc over and over again.

Can anyone help?

Thank you.