Unexpected lack of control
Usually once I become lucid I have complete control over objects I'm interacting with.
However, this morning, I become lucid inside a car at night (in the dream).
My first thought was to get out of the car as quickly as possible and do everything I could before I wake up.
The car door didn't open, though.
It rattled in place a little, then stopped. So I tried to open it again. It did the same thing. Neither time did I expect the door to be locked, I expected it to open on my first attempt without much thought. On the second attempt, after the rattling of the handle, I was struck by a horrible feeling of dread that something was wrong. Everything went dead silent, all ambient noise ceased. I was hit by the thought that something terrible was going to appear (you know the one) and blacked out/woke up with only a short flash of what the dreamworld was conjuring up to fit my expectations (a cracked white face with empty, bleeding eye-sockets).
Was this some kind of half-lucid nightmare, or what?