Guess the lesson

One night, I saw a tunnel. I saw a multitude of colors scramble over each other. A thick veil of fog hid the end. Screams, shouts, roars, and much more rang throughout. Slimey grime covored the walls and floor. Rot and ammoniun assaulted my nostrils. As I traveled, my solitude revealed a lurking claustrophobic feeling. Liquid concoctions rested on my tongue.

At the end of the tunnel, a hole waited below a chimney. I turned to notice that the tunnel's veil disappeared. I saw agony reeling over, fear cowering along the wall, rage bellowing, joy cheering for no one, disgust making that awfully sick look, despair wailing. I slowly turned back to see an elevator in the wall, the hole filled. I walked over the filled hole to the elevator. Now where to go........