A/N: Testing the waters here a bit, I've never written Supernatural before, or even posted anything on FF before! However, I'm hoping this turned out well enough. Eventually, I'll write something more than 500 words, maybe even something chaptered, but I'm sticking to short little oneshots for now. I wrote this right after 8x02, probably about ten minutes after it ended, contains purgatory spoilers if you haven't seen any of season 8.
White, foreboding light filtered ominously through dark, thin pillars of dead trees. An angel sat in a clearing, knees hugged uncomfortably up against his chest as he stared out over a tiny creek, the small pebble beach cold against his skin. He felt his body shudder with the torment of his last attack, he didn't know the extent of the damage, it didn't matter; he could still move. He didn't know how, but he could. Every fiber in his body, his mind, and his very soul told him to give up, to stop running, but he could never just quit, not as long as he heard the voice in his head, his voice, Dean Winchester's prayers. They kept him alive, kept him running, gave him hope in the most selfish way imaginable.
He knew Dean wanted him to be near, wanted him to go where he was, to help him, but he couldn't. If he went to Dean, Dean would die; Dean would be torn to shreds, broken, and he couldn't handle seeing that man destroyed, wrecked further. He didn't even want to imagine what the hunter was going through right now, but he was alive, his prayers at night proved that. He might have been hurt, and maybe he was dying inside, but he would survive, without the angel, without Castiel.
His own conviction though, was worse than anything he was faced with in Purgatory. Castiel was terrified of every decision he made, even the thoughts in the back of him mind, telling him, imploring him to make a choice on one thing or another, whether to run or hide, live or die, to go to Dean or to stay away, but all he could do was keep running and staying away from his own questions. Some would argue that in doing so, he was making a choice, but if he let himself think hard enough, he eventually would ponder if his action was ruled by intent or desire, and maybe, in the desire, is where his decisions were made.
Of course, Castiel never let himself get this deep in his thoughts, he couldn't. He was far too brain-scrambled to think past anything that wasn't absolutely necessary for his survival. That was his excuse. The real reason was because he couldn't handle it, but in the back of his mind it was there, every thought, every guilt, all trapped behind a barrier that he could easily break himself if he so wished it. He didn't though, he didn't want to face his recent past mistakes. Castiel was afraid of what he might do to himself if he owned up to—no. He couldn't deal with this right now.
He couldn't keep up with this pyrrhic victory of his mind and soul much longer. He would eventually break under the pressure of it all, but not yet. For now all he would do was keep running.