Talk:Rose/@comment-40193977-20190727215552/@comment-27794543-20190729005252

From the writers perspective: Because Rose living did not serve the plot. They needed Sanctum to be desperate, without any hosts, willing to take hosts from Spacekru by force.

From CoG perspective: From the episode, it seemed many, if not the majority, of them were quite willing to kill Rose even if it was still 10+ years before she could become a Prime. Eliminating hosts is a good way of preventing future Primes.