Absolute self-control.

The moment I found myself deserted, I knew exactly what to do.

I did precisely the same thing that I would have done had I been left alone in the Mammoth Cave, or the Cave of Fingal, or any place of the kind.
"I stood perfectly still! "If you will always remember to do that," and he looked as well as he could from one to another of us, "you need never be frightened, no matter how dark and lonely a cavern you may be left in.

Strive to reflect that you will soon be missed, and that your friends will naturally come back to the place where they saw you last.

Stay there! Keep that important duty in your mind.