Doctor Who: 10 Terrifying Moments In Under The Lake
2. The Silent Message
"Dark, sword, forsaken, temple..."
Only towards the end of the episode does the Doctor - and the audience - realise that those silent mutterings on the ghosts' lips are actually a message. Coordinates to another place in the galaxy in fact. In order to understand what is their purpose, the Doctor puts himself in the firing line by walking into the Faraday cage with the ghosts.
Despite his comments that they can't harm him, it is another nail-biting moment as he comes face to face with the ghosts a second time. Watching them staring at the camera screen, muttering their message is a chilling image that will stick in audience's minds long after the episode has aired.