Energy shield. [Narvin promptly voices his opinion.]

In addition to testing ways of bringing the dome down, I would like to see if it's possible to trace the origin of the dome to its source, perhaps by tracking an energy signature or a power nexus. It may not be the priority of the people in the town, but I want to know who did this and why. [And, always in the back of his mind, the question of whether they are a potential threat to Gallifrey.]