Possible Clues:

• Space made by burrowing creatures in fruit, wood, books etc
• In theory, shortcut in space around Golden Mile is complete
• Hypothetical tunnel in space-time
• Hypothetical space-time shortcut
• Zero room in entire trans-dimensional passage
• Underground tunnel undamaged when penetrated by soldiers -- 1,000
• Cavity make in wood by burrowing larvae
• Opening on a sci-fi program
• Soldiers needing minute to enter inviolate spacetime shortcut
• Sound around shape initially absent in hypothetical tunnel