Fan Casting Doctor Who Day of Time (2016)

On the "worst day of the Time War", the Doctor, Fey and the Sisterhood of Karn fought the Daleks and the Morlontoa of the Seventh Sky on the Dorian Nexus. The Doctor constructed a machine that would fire pulses of pure reason at the creature to defeat it. While this was happening, Fey ordered Time Lord Captain Dolios to get the childlike inhabitants of the planet, the Loshann, to a TARDIS. The Sisterhood was then struck by a stream of pure chaos, leading the Loshann to be hit by the spores of the Morlontoa. They were quickly inverted, turned into monsters and attacked. To save themselves and other Loshann on the planet, the Doctor ordered Fey to shoot each of the Loshann. After she did so, the Doctor's machine failed, and the planet would fall anyway, rendering Fey's killing of the Loshann meaningless.