The Doctor hates to do this, but he can’t see any other option. The tunnels are a veritable labyrinth, and brilliant though he undoubtedly is, keeping track of the route he takes is going to be impossible. He can’t afford to get lost down here; he may never find his way out again!
“Sorry about this,” he mutters as he firmly ties the yarn end to a protruding rock. “Your sacrifice is appreciated.”
He and his scarf have been through a lot together, but as he sets off, unravelling it behind him, he knows it’s never been a greater asset.