“In case of what?”

“Well, in case.”

Bill, had to be content with that, but he was too much excited to wonder what Antony meant.

“Righto,” he said. “Go on.”

“Well, we’ll just make sure we can get back again, first. It really wouldn’t be fair on the Inspector if we got stuck down here for the rest of our lives. He’s got enough to do trying to find Mark, but if he has to find you and me as well⁠—”

“We can always get out at the other end.”

“Well, we’re not certain yet. I think I’d better just go down and back. I promise faithfully not to explore.”

“Right you are.”