do nightmares help cause lucidity in dreams?

[intheworldofnim]

the first two lucid dream came after I was in a fear incudcing dream usually involving the prospect of a tornado. the first one I was only semi lucid but before it, the family was trying to get away from a tornado(which looked more like smug clouds than actual tornadoes) we crashed and then I started thinking of the tornado touching down on us and then suddenly I hear this load sound and I feel something pushing down on me then suddenly it stopped and I'm not sure if a woke up and did an unintentional DIELD but I was in the same area where trees were scattered but everything was quiet, no tornados. I suddenly out of nowhere start flying over some branches, I don't even remember how, I remember flying and then punching some deformed looking guy, then after that I flew a bit higher and told myself I was lucid dreaming and started spinning sideways then woke up. the whole time during this second part of the dream I felt a strange sense of awarness that it was a dream but I wasn't shocked, I still sort of treated every thing like it was normal. I'm pretty sure it was a semi lucid dream, either a layer zero major that became a layer 3 minor or it was a layer 2 minor. But anyways I don't remember exactly when I became lucid, I went straigt into the dream with this feeliung of being in a dream which made me question whether this was real or not. the second dream I think I was in a higher layer of lucidity. In this dream I actually remember when I become lucid but the thing about this dream is that I can't recall what triggard it, it just happend radomly. the second nightmarish dream also involved the danger of a potential tornado. that potential tornado became what looked like a colorful wormhole that touched down on the ground like spinnong lights 20 feet from me. anyways I turned the car and like the last dream I felt surrounded by the storm, dark mist surrounded my car. things started to shake just like in the last dream and the fear was at an all time high then suddenly I just spontaneously became lucid. I said, wait, I'm dreaming and I make the storm dissapeared and a castle amusement park where I just flew out of the car and into the sky and started shooting fireballs from my hands (this dream later turned into a regular one). anyways the main thing is I have no clear understand of what exactly made me become lucid, it just happend spontaneously. I hear many people talk about certain dream signs they notice which allowed them to think "thats not right" and then become lucid from there due to a particular occurance. For me it was a completely random, spontaneous event, no illogical dreamsign sparked it. so I'm wondering if nightmares help spark lucidity. fear makes people more alert so maybe a nightmare helps turn on the part of the brain that deals with self awarness. anybody have any ideal?