Beyond this, however, was revealed an unbroken wall.

Again Boris touched a certain spot, and now this wall, seemingly solid and unbroken, gave way, just as the oaken panel had done.
"Even if they discovered the panel, you see, they would not have the secret," said Boris.

"I will show you the exact spots you must touch.
Then if they come, you can reach this place by yourself.

Once in here, you will be safe.

Carry an electric torch always with you.