Prince Hans 'Shadow' Westerguard of the Southern Isles found himself licking the salt off the ground. Yes, it was gross, but occasionally he had to let the dog-brain win a round to keep it occupied.
He had wandered to the salt mines in an effort to get clues to the plan. All he could see was a canal leading from the fjord to the mines themselves. It seemed stupid and pointless. Why flood the mines? If anything, Elsa was more powerful with water around!
Hans laughed internally. The dog was also happy to taste the salt rolling around on his tongue. Speaking of which, Hans said to himself. The dog ambled over to the fjord for fresh water. Shadow/Prince lapped it up. The human part of the brain sat in silence, replaying his time with Elsa- her crying when he tried to kill her, and her crying when she found the note...
Wait...
Hans lifted the dog's head in thought. Tears were salt-water (of a sort) and... they didn't freeze. Calling to mind his experience on the ocean, Hans realized something; saltwater didn't freeze. Elsa couldn't freeze the water from the fjord if it was mixed with salt. If she couldn't freeze it, she was powerless... and would drown.
Noooooo!
He had to save Elsa. Anna was second priority. Well, third, after Sophia. Maybe fourth if Kristoff was in danger.
Kristoff...
He could help! Hans knew where Anna was. And, unlike Elsa, he had no objection to being helped. The prince took off at a run for the cottage, barking as loud as he could.
"Shadow!" Sophia cried. He unfortunately had to ignore her.
He was about halfway to the cottage when he ran into a familiar-looking sled pulled by a familiar-looking reindeer.
Sven!
Even though the two had always fought, the dog could not be more delighted than to see the large deer. Kristoff peered out from the sled watching the dog bark.
"What is it boy? Is Anna stuck down a well?"
Hans sighed, then took off for the mines. He leapt into the canal and barely squirmed into the hole.
Elsa or Anna? Obviously, his heart screamed for Elsa, but he definitely owed Anna. He listened carefully, sniffing her out. Eventually, he came across her stuck in a trap. She was looking back, both dehydrated, and tired.
"RUFF!"
Anna's eyes light up in recognition, "...Shadow? Shadow!"
Her arms flew around him. She clutched the collar, "Ouch! This must be so uncomfortable for you...!" Click.
Don't get too used to me being nice, princess, I'm just here until Kristoff can find you.
He didn't have to wait too long before Kristoff broke into the tunnel using his ice pick.
"Anna! My love!" They embraced warmly. Anna rested her head against her boyfriend. Hans watched with a small degree of envy. Kristoff and Anna had something he would never have. Once he saw Anna scramble to safety, he finally got to look for who he came here for;
Elsa! Elsa!
He barked as loud as he could, sending echoes around the cave. He snuffled his heart out, finally finding her in a mud puddle.
"What...?" She was confused. Burst after burst of blue light hit the water, "It's not freezing," she kept murmuring over and over again in a worried voice.
Hans ran up and licked her face in joy.
"...Prince, but... what're you doing here?"
He barked again. What, like I'm going to start talking now? Come on, who ever heard of, or from, a talking dog?! Let's get out of here!
He grabbed the hem of her dress and started pulling her back the way he came. She was talking- something about finding her sister and guilt and a bunch of other stuff he ignored because he was trying to save her life!
Finally, they spotted the way out, illuminated by a single beam of light. Hans slowed his trot, relieved it was almost over. But his relief was premature. Within seconds of them finding the way out, water burst down the tunnel.