Master's Naval Sabotage Call Device

The Doctor describes the Master’s calling device as a jury-rigged communication tool fashioned from stolen naval components, using this narrative device to collapse Hart’s fantasy dismissal and pivot to actionable intelligence—implied presence rather than physically shown.

The Master’s calling device is indirectly implicated through the Doctor’s reference to the stolen spares and the confirmation of their theft. While not physically present, its narrative role as the tool enabling the Master’s control over the sea creatures and leverage over Trenchard is central to unifying the scene’s disparate threats under a single, dangerous source.

Though physically absent in this segment, the calling device is referenced contextually as the reason the Doctor pivots away from Sea Devil warnings. Its existence becomes a bridge from absurdity to credibility, as the Doctor implies Hart's skepticism can only be challenged through tangible sabotage.

The Master’s calling device, fashioned from the stolen spares, is implied rather than shown; the Doctor references its existence using the spares theft as evidence of a direct link to the alien signal or control mechanism. It becomes the symbolic pivot from abstract theory to confirmed sabotage.