"Sure," Jack says, pausing in his labours and raising his eyebrows. "And I'm digging, Doctor. What does it look like I'm doing?"
He's made a channel about three feet down and four feet across, and his hands are very cold, but he feels like he's making progress. He rubs his hands together and grins.
"Okay, I didn't really know what I was going to do when I started, but I think I do now."