I just found out the answer myself. "Q" tries to start the shell, then dutifully informs me that there is no shell to start. Very nice of it to be so informative.

Now here's my follow-up question...

I'm only interested in poking around for fun and to see the file structure. The stability of the unit is more important to me than the ability to mess around at the command prompt. If I installed the developer kernel, would I be compromising the unit's stability? Are there more bugs in the developer build than in the retail build?