The light at end of the tunnel?

Sometimes, a word/ a phrase/ a song can take you down a tunnel to a time/ a place/ a person even if you don't want to be there. And once you're set in motion, it is beyond your control to turn around, you just keep falling, and falling. The only saving grace is to remember  that when the tunnel ends, you'll still be on the side you started on.

There is no light at the end of the tunnel, for all you know, you're getting sucked into a to-be black hole.