The most beautiful sequence in Before the Flood is the quietest one. Cass is deaf and cannot hear the monster behind her dragging the ax. When the soundtrack goes silent every time the camera focuses on Cass face we feel complicit in her fear. But Cass is far from a coward or an idiot. Shes learned how to adapt in a world without sound and to trust her instincts. She does not hesitate upon feeling the vibrations beneath her feet but turns immediately and barrels her way through the ghost before it has a chance to react. Cass gets her happy ending only because Lunn finally learns not to hold back. This episode is not about monsters its about time and how fleeting human lives are. Lunn seizes the day but Clara never did. She used her relationship with the Doctor as an excuse not to get closer to Danny. Her choice to time travel however is not the problem but rather her dishonesty. She could have shared her life on the TARDIS with Danny. Certainly she could have talked the Doctor into taking him with them but she didnt want to. She selfishly wanted to keep everything for herself and I have a feeling shes well on her way to losing it all.