To clear things up,

[Pink Stars]

Just a few minutes ago, I read about one person's Lucid Dream experience, and they were debating whether you can die (in real life) if you died in your dream.
And for anyone asking this, the answer is.. HELL NO.
The chemical released in your brain AND the chemical you release when you die are one and the same. It's called DMT, one of the strongest (if not, THE strongest) hallucinogen in the world. If we could die in our sleep, that would mean that DMT is VERY dangerous, but people who have researched DMT found that it was actually one of the most harmless drugs/chemicals in existance.
So, say you jump off a cliff in your dream, and then you died while DMT was already being released.. Then death would be nothing at all, just blank, blackness, a neverending void of space, because since the chemical that makes you "go to heaven" was what killed you, you're shit out of luck.
It's complicated for me to explain, but i'm hoping that most of you will understand. DMT is not dangerous, nor is lucid dreaming.
I do not know if this is correct or not, but I have also read something that states DMT is stored up in the body during the first 28 days of your life, which also proves my point, because I HIGHLY doubt that your body would stock up on a chemical that could easily kill you, and release it every night when you sleep.