Sunny had a lot to consider.
He wanted to give Rain the best chance of, if not thriving, then at least standing on her own in the war between Song and Valor. The problem was that there were only a handful of individuals in the world who could stand their ground in the sweltering hell of Godgrave.
The rest of them — the Awakened soldiers, the Ascended officers, even the Transcendent generals — were really out of their depth. They were not meant to be here, in the middle of a harrowing Death Zone, and they were definitely not meant to spill each other's blood for the benefit of two callous Sovereigns.
If even Saints could not guarantee their survival in the war, then mere Awakened like Rain could only rely on luck and good fortune to survive. Of course, Rain had her faithful shadow companion to keep her safe… but she did not quite know how far her teacher was willing to go to protect her.