Amethyst Viral Containment Station

 was a depository for dangerous viruses used in the Viyrans' war. It was a maximum security facility. The station was near the core of a planet orbiting Amethustra, at the universe's edge. The Sixth Doctor claimed that it was "one of the remotest periods of space-time the old girl's ever travelled in". It was destroyed on the orders of the Dalek Time Controller so the viruses would be scattered through space-time. (AUDIO: Patient Zero)