I want to repeat that the dark areas in dreams mark where the play of inner light ends. The play of inner light is known as dreams. If you lucidly enter the dark area within a dream, you will leave the dream and experience awareness itself.
You may note that there are protectors of the dark areas who direct you away from them. They can be ordinary people, wild animals, even gurus. Usually your own fear of the dark areas is sufficient to keep you away from them.
The dark area is prior to all light. The instruction to “follow the light at the end of the tunnel,” at your time of death, makes sense if you want to be re-born. Otherwise move into the blackest black (not simply a dark blue, for example) and you’ll be gone. You’ll know that at the time of death and, as in a dream, you’ll be directed away from the dark area and toward the light. You have to be strong at that point. Most are led directly to the black area or to the light or to some intermediate level without lucidity about what’s happening.
All dreams, all existence arises in the dark area. It’s a very small event, that arising. Brains have been evolved to make that incredibly small event incredibly huge. By being a lucid in a dream, or within any experience, you can see that. You can see what you are.