Nightmare before Halloween

I had a really nasty nightmare the other night. Generally my dreams are very vivid and detailed and I have excellent recall, especially if I write it down upon waking. Even better if I don't move and just recall aloud. Anyway this concerns my grandmother. She's driving, my grandfather is in the front seat and I'm sitting behind her. We are talking, everything seems fine. Then we are somehow being cut off/shoved into oncoming traffic by a car next to us. That car is struck head on and quickly disappears past us on the right as we crawl to a stop. Another car approaches, hitting yet another oncoming car. Body parts are flying and hitting our car with sickening wet thuds. Suddenly we are struck. Somehow I am now in the front seat next to Grandpa. He says "Where is Grace?" and he looks in the back seat. The look of absolute horror on his face says it all. I don't dare look in the back but the blood spatters tell the story. I am trying to hold him and comfort him and he says (in a WILDLY uncharateristic expression of emotion) "I can't even hold her!" his eyes are brimming with tears and I'm telling him it's crucial we don't move her (even though I haven't looked and her head could be missing for all I knew). At that point I woke up rather upset, heart pounding, etc... Hopefully not prophetic... I haven't called for fear of finding out something bad happened. Silly I know but what can I say? Why can't my erotic dreams be this realistic and detailed? Oh wait...they are.