I have a qyestion about their fight.While Unalaq wasn't in the Spirit World,why didn't Korra use that specuial waterbending technique to destroy him??She didn't want him to grow inside of her or she felt like she didn't have the time to do that?
Also do you think that it is possible that if she locked Vaatu is the Tree of Time during the Harmonic Convergence he could be released again?