Hukif came up with this, and asked me to post the idea here for MMers to try.
Basically, it begins with the question of why people get lucid from nightmares. The answer in part was not because nightmares scare you, but
because you care about your survival,
because you get invested in protecting yourself from the nightmare, your mind will assess the threat and let you know that the threat is not real, it is a dream.
To help this along into a better way of LDing, you can try this RC during the day -- any time there is something that scares you, or causes a response in you, positive or negative, even small things...pay attention to that feeling of "caring" about your environment and RC. Hopefully this will increase your awareness and help you get lucid not only more in your nightmares, but your regular dreams.
If anyone is willing to give this a try, please post here and let us know how it went for you.