i actually agree with Issacs decision, if the tower is really as bad as he thinks, honestly I feel like keeping rubia alive until at the very least another 2 years for skele to come around, she's probably gonna be completely broken. I don't even think skele can do anything about that to save her, body or soul or mind so in the end if issac did let her live Skele still wouldn't have "saved" her and it would have just prolonged her pain.