Author's Note: To those who reviewed or added this fic to your favorites/follows, thanks so much for the encouragement. I really needed a motivation booster back there, and I'm sorry if I sounded like I was whining for attention or something. I hope you guys enjoy this next chapter ^_^

On a side note, my pace of writing will probably slow down a little. I still ask myself what I was thinking when I signed up for summer classes... Sigh.

Disclaimer: I do not own Rise of the Guardians, How to Train Your Dragon or Portal/Portal 2.

Hypothesis

Chapter 7: Falling

:: The Enrichment Center promises to always provide a safe testing environment. In dangerous testing environments, the Enrichment Center promises to always provide useful advice. ::

Yeah right, Jack thought to himself, frowning as he followed his partner into the next test chamber. With no small amount of guilt weighing on his mind, he snuck a glance at the band of blue wrapped around Hiccup's left arm, mentally taking back everything he had said about the tests being completely harmless.

:: For instance, the floor here will kill you – try to avoid it. ::

The entrance doors slid open with a soft hiss, revealing a room filled with various platforms suspended above a deep pit. Peering over the edge of the ledge they were currently standing on, Jack saw that the bottom was flooded with some sort of muddy liquid under a layer of dense green gas, neither of which seemed particularly inviting.

"Well," he gulped, turning to Hiccup who was watching him curiously from behind, "it's no swimming pool down there, so we should really watch out step here."

The brunet nodded his head mutely, hefting his portal gun (the bullet wound didn't interfere with his aim, but Jack noticed that Hiccup had become slightly slower in firing his portals) in preparation.

They proceeded with caution, hopping from platform to platform as they worked their way through the test chamber. Buttons were pressed and switches were activated, and Hiccup quickly discovered that some of them were connected to certain movable platforms, controlling their movements around the room.

"I think I see the exit!" Jack exclaimed excitedly, racing ahead on an elevated row of platforms lined up to lead towards the next area. Hiccup lagged behind him, panting as he tried to keep up.

"Jack, wait up!" he called out, huffing in annoyance when the other test subject seemed to ignore him and disappeared behind a wall after reaching the end of the row. The brunet slowed to a stop halfway through and bent over, resting his hands on his knees as he caught his breath. Given that there was a timer keeping the platforms aligned, he didn't dare to linger for too long. Hiccup gave himself three seconds before straightening up and doing a running jump towards the next platform.

It was when he was already in mid-air that the platform in front of him suddenly started to move to the left, and as much as he twisted his body to correct his trajectory, he realized too late that he would not make it in time.

"Shit!"

Hiccup's feet landed on thin air and he felt himself falling for several heart-stopping moments. His right arm was (quite painfully) nearly jerked out of its socket when he managed to grab onto the edge of the platform, hanging precariously for dear life as he swung dangerously from the momentum of his fall.

:: You were right, Blue. Green was dumb enough to fall for your trap. ::

The brunet growled and shook his head, trying to expel the poisonous robotic words from his mind. He couldn't deny that he had his doubts, but he refused to believe that Jack had planned this. Grunting, he tried to raise his other hand to get an extra grip on the moving surface, but the bullet wound on his left arm chose that unfortunate moment to act up again, eliciting a soft whimper of pain. It was all he could do to maintain the hold on his portal gun, but the same could not be said for his right hand, which was slowly losing its grip on the smooth metallic surface.

Hiccup wanted to shout for help, but the growing fear spreading through his body paralyzed him, forming a lump in his throat as he choked on the words. Some dark part of him whispered that Jack was already too far away, and besides, who said that he would come and save him anyway?

The sound of his heart pounding wildly in his chest was all Hiccup could hear as his fingers started to lose their purchase. He squeezed his eyes shut in anticipation, bracing himself for impact when they finally slipped, leaving him to fall freely to his death.

"Gotcha!"

A gasp tore itself from his mouth when two cold hands suddenly clamped down firmly on his wrist, keeping him suspended over the noxious mixture swirling beneath him. Hiccup looked up to see Jack straining to pull him to safety, gritting his teeth as he leaned back and used his weight to heave the brunet over the edge. Once his feet touched the flat surface of the platform, Hiccup collapsed onto his side and panted in relief, breathing out a grateful "thanks" as Jack crawled over to him.

"I thought you –" the white-haired teen faltered, his eyes wide with the shock of nearly losing his partner. His shaking hands ghosted over Hiccup as if to assure himself that he was really there. "I heard you shout and you weren't there when I looked back – I thought –"

"Hey, hey," Hiccup's good arm reached out to grab Jack's hand, causing the other test subject to flinch at the contact. "It's okay… I'm okay," he soothed, looking into ice blue eyes as his thumb rubbed gentle circles on the encircled pale wrist. "You caught me –"

"I left you behind," Jack whispered with regret, swallowing hard. "I'm sorry, I didn't mean to – she said you fell for my trap, but I swear I didn't –"

"Jack!"

Startled, the white-haired teen jerked upright and stared at his partner's lopsided smile with confusion, faintly registering the grip on his hand tightening ever so slightly.

"I know, I believe you," Hiccup said sincerely, sitting up to look Jack properly in the eye. "Jack, you saved my life. Thank you."

"You saved mine first," Jack finally cracked a familiar grin, much to the brunet's silent relief. "Guess this makes us even then."

:: You both made it. It seems no matter what I try to do to pull you apart or destroy you, you just keep going. Keep testing. ::

They snapped their heads towards the nearest security camera hanging from the far wall on their right, staring at it in disbelief. It looked like it had all been just a test, but Hiccup caught Jack's frown and shared a nod with him. Clearly there was more going on than what the voice was telling them, and if the increasing level of danger in the recent test chambers was anything to go by, they could tell that something big was going to happen soon.

:: Congratulations on completing the test. You two really are the best cooperating testing team I could ever ask for. ::

"For the record, I never told her anything," Hiccup said once Jack had unlocked the final door and met him at the exit, earning a puzzled look from the other test subject. "I mean, all those things she said about not trusting you and doing all the work…" he clarified, trailing off uncertainly as they walked towards the next lift.

"Thanks Hic, but I knew you wouldn't have done anything like that," Jack winked at him, feeling as though a large weight had been lifted off his chest at the confirmation. "I didn't either, in case you were wondering," he added, taking note of the way Hiccup's shoulders imperceptibly sagged with relief. It seemed that the voice had played them both, creating friction and bad blood between them to test their friendship, but at least it was all over now.

Still, there was something gnawing at Jack, something that caused an indescribable ache in his heart when he thought about Hiccup getting shot and falling off the moving platform. Despite the tests requiring them to split up often, it didn't sit well with him knowing that he couldn't be by Hiccup's side all the time. He couldn't explain the sudden uneasiness that flooded his senses. For some reason, Jack felt that something more permanent was going to separate them soon, and he got the feeling that it was going to be much worse than the conflict that had made them doubt each other.

"Hiccup?" he asked tentatively, hesitation heavy in his steps as he slowed to a stop. The brunet turned around to face him and cocked his head slightly.

"Yeah?"

"Promise me… promise that no matter what happens, we stay together. Okay?"

Hiccup was slightly taken aback by the intense look in Jack's eyes, but he smiled back confidently. "Always," he promised, reaching out to lace their fingers together. Giving the white-haired teen a gentle tug, he pulled him into the lift, keeping their hands linked all the way to the next test chamber.

:: The experiment is nearing its conclusion. The Enrichment Center is required to remind you that you will be baked, and then there will be cake. ::

Author's Note: Portal fans, you know what's gonna happen next. Stay tuned.