Everybody's still dead. Sarah still killed them. But in order to earn the Comedy Ending in the first place, you have to play in the most benevolent, compassionate way possible; Sarah has proven herself a thoroughly good person when not in the artefact's thrall, and Arthur is forced to admit this to himself. Instead of simply offering her escape and redemption, he grudgingly creates the birthday party scenario for her, where everyone appears to be alive and happy and the previous torment is rationalized as all being part of the setup. After all, what could be a better reward for Sarah than redemption and escape from the station, to live her life always remembering what she did? The chance to die peacefully, in happiness and comfort, with the weight of her sins completely removed from her mi