So, you know the part of the Tama-Go that slides off the top to allow figures to come on? Slide it off the way you normally do. Then, with the curvy part of the piece facing up, pry off the glass plate on its groove. I discovered the trick after being as worried as you about wrecking it.
This was hard to explain the process, so if you have any questions about what I just said, feel free to reply.
~Amat