We don't know if the life that would have been sacrificed that third time to reverse the first two sacrifices were non-sentient or not. Considering that the Ascians later on with the Rejoining plans have no qualms sacrificing the sentient Sundered life, it's not a stretch to assume that they were. The reversal of XIV's theme about how the Final Days Ancients and later Ascians are willing to sacrifice those that will walk after for those that walked before.