That's when the idea of an escape tunnel came to me.

Why shouldn't the middle class have an escape tunnel?

To her way of thinking, the palace had to have at least one escape tunnel.

"We've got to decide if this place is anywhere near the escape tunnels."

He must have had an escape tunnel out of the tower.

"I know of a private escape tunnel for the ward."

"He took off through an escape tunnel and it blew up on him."

In a moment he had discovered the escape tunnel's secret door.

Also an escape tunnel and a bridge to the shore.