> everything about the dream continuing to be autonomous as before becoming lucid, but if I wanted to do something, I could add that element. I definitely could still be surprised

I may have overstated what I said. The environment continues to be dynamic, and characters enter and exit and cause their usual mayhem (alongside me). But if something unexpected happens, there is–in my mind–a theatrical explanation for it and thus a plot-driven solution. The stuffed animals are upset I'm going to wake up and kill them, so I put them in a zoo where they believe they continue to exist after I stop dreaming, et cetera. (And sure enough, they're there next time I'm in that "place".) If you're trapped somewhere, you know an exit will materialise because you're the main character, and sure enough, it eventually does. If I break something I love, I know something will happen that makes it whole again. When anything that happens can be undone, action is robs of its meaning.