It was then and there, as the trio let themselves lay down and catch their breath, that their attention fell on the one thing they'd ended up carrying with them from the crossroad. Who was still surprisingly alive, and unsurprisingly terrified. The three of them exchanged glances, all unsure of what exactly to do, and it was Pinkie who took action first. She approached the white unicorn with a potion, stored in a proper vial and not a balloon. "Promise me you'll stay quiet," she softly said, then she poured the contents onto his paralysed body.
As could easily be expected, he did not stay quiet. He in fact attempted to do the opposite. Precisely because it could easily be expected, the other unicorn in the room was ready, and held the soldier's mouth shut with his magic as soon as he tried to scream. The soldier tried to use his own magic, but he found it still wasn't answering him despite his movements no longer being restricted. After a bit of attempted thrashing around, he swallowed and went silent of his own volition. "Keep quiet or we freeze you up again," Applejack said to him.
The stallion nodded, and his mouth was released. He spoke more quietly, but rather defensively. "You threatened to murder me," he hissed at the three ponies. "Give me one good reason why I shouldn't rebel against you."
"I wasn't actually going to kill you," Pinkie said. "I would never, and Twilight wouldn't like that anyway. I was just bluffing."
"I wasn't, and I would have killed you," the other unicorn said flatly. "That's why I was the one pointing my horn at you."
"Well, it's not like your comrades out there were against killing you either," Applejack interjected. "Didn't look to me like they cared if we did something to you or not. In fact they seemed pretty eager to do the job themselves."
"They did do that." The white unicorn stared into the distance for a moment. "They almost murdered me," he said, more quietly. Then he focused on Applejack. He tilted his head, studying her. "How curious," he said.
"So?" the other unicorn asked.
"So what?" the soldier snapped towards him. "I'm your prisoner of war. A rather useless one to you considering what you just saw happen. Do whatever you want, but don't expect me to cooperate. I'll only avoid stabbing you in the back out of respect for basic warring decency, but don't think death is enough of a threat for me to follow you around or help you. I'd rather die trying to escape you than fight at your side or obey your orders."
"You'd really rather go back to the ponies who almost shot you dead?" asked Applejack.
"Rather than be with the enemy? Of course," defiantly said the soldier. "You would do the same in my place."
"The enemy, huh?" Applejack moved closer to the stallion. "What are you fighting for? Not your side. You." She stood in front of him and stared him down. "Because I'm fighting to defend my country. Because you attacked us. You invaded us, unprompted, planning to take over our cities, and if we didn't have a way around it you would have slaughtered our soldiers and placed our citizens into slavery." She slammed a hoof in the wall behind him to the side of his head as she pushed him back against it with her presence. The impact left a few cracks around where she'd hit. "So tell me. Why are you fighting? Why are we the enemy?"