Anna was frozen in spot – she did not know what to do. Should she go to Kristoff or to Elsa? She needed Kristoff to help her thaw but Elsa was fighting with Hans at the moment.
As if in slow motion, she saw Elsa fall and Hans prepare to swing his sword.
'I must go' she thought, as her legs started to move – slowly – towards her sister. She thought of her sister and all of the sacrifices she had made because of her power. She thought of the good times and the bad, and these thoughts coupled with her desperation, allowed her to go faster.
But it was not enough, and she froze seconds away from protecting her sister.
The sword dove slowly into Elsa's shoulder, but was quickly iced over within the wound. When Hans tried to pull it out, it was so cold it broke.
Elsa could feel the pain, albeit distant, numbed by the cold within her, and she cried out in fear and pain. The storm picked up within the whole country – buildings and carts were moved by the wind and ice, and visibility was impossible throughout the lands.
Only the eye of the storm was safe. And it is in this eye of the storm that Elsa slowly looked up and around her. Hans was frozen from the feet up to the torso by her fear and could not move – this did not stop him from glowering angrily at her, and mouthing words that remained unheard above the sound of the storm. Kristoff and Sven had only just reached Anna and were trying to find a way to warm her up – a thin layer of snow was already gathering above the ice. Anna – her sister – stood there, a frozen statue of desperation and Elsa could no longer look away.
"NOOOOOOOOOOOOOOOoooooooooooooooo"
And the snow stopped. The land seemed frozen by time now that the storm had abated. Frozen under a thin layer of ice and snow.
"Anna – what did I do?!"
As she saw Kristoff, Sven and Olaf crowd around Anna and try to provide for her the warmth she needed, Elsa's feelings of guilt and pain grew. She was no longer scared – what she had feared all these years – ever since meeting the trolls as a child – everything, had come to pass.
She had to leave – disappear somewhere she could truly be alone, and put nobody at risk.
And so, she ran.