[SPOILERS BELOW]

The night before the empire attacked Falaina, Sienna was told to not leave a displeasing corpse behind. Then, during the last episode, Shuan says, "You'll feel better if you pretend it has nothing to do with you." He was speaking to Ouni, who replied, "So that's how you lived." Shuan then had a flashback of Sienna tearing up and him slicing the grass. Can someone explain the symbolism and reason behind all this? ;w;