It turns out that I've had a lucid experience similar to the one you've had, lucidboy.

I'd become lucid and I was in a theme park and after walking through a bunch of doorways (something I'd been having the hardest time with; I'd always get kicked out of a dream by going through a door...) I'd stopped and decided I was going to summon a very specific DC. I turned around, and I swear I could feel the dream reality shifting; it was going to happen. But right as I was about to make my request verbally, a male voice (it sounded like it came from inside of my own head or from the sky) told me, "No." and suddenly the energy I'd felt building to summon my DC vanished and I knew I couldn't do it. I felt like my dream was high-jacked and, pissed, I shouted to the ceiling, "Why not?" and he told me something along the lines of 'now is not the time.'

I still tried to summon my DC, but the simple fact was that I couldn't do it. And that was painful. I ended up sitting on a curb in this dream theme park, moping, and angry before I tried to fly and fell out of the dream. It was the strangest and most unnerving LD I have ever had, and probably the one that bothered me most. This voice wasn't a regular DC either. He was sentient. It almost felt like he existed outside of the dream and (apparently) had ultimate control over what I could and couldn't do while in it. The experience itself didn't frighten me, per se (I like to think I'm open minded about things like this) but this was the first time I'd actually encountered something like him and I was a little disturbed. Afterwards, I couldn't remember my dreams for a month and that scared the shit out of me.

I'm not sure what the dream meant, but the experience made me wonder just how much control and power I really have in the dream. Made me wonder just what else it out there, you know? Spooky, but thrilling all at the same time, huh? Anyway, I plan on trying to talk to him again, next time I get lucid, and find out who he is and what he meant by 'now is not the time'. Maybe you should try and ask her who she is and why she was asking?