User blog comment:Miskos3/Fairy Tail 541: The Magic of Hope, Review/@comment-4449950-20170626115211/@comment-7418318-20170626140051

Erm... inside the sphere time was stopped, so that to the people inside it felt like they traveled through time. What good would it do to keep everyone frozen for eternity?

Even if Acnologia would die of old age however many centuries or millenia in the future, how would Mavis know when it's save to come out?

And could she really have frozen the entire world while keeping Acnologia out? Because if not and she's only saving a few dozen selected friends, that's be a big asshole move to the millions or billions of others whom Acnologia would have slaughtered.