She ran until her legs ached, and her chest felt as though it would burst. Running helped. Not because it got her anywhere special, but because the effort involved helped her to clear her mind. When your mind is full of thoughts about getting more oxygen, and thoughts about the pain you're in, there isn't room for other thoughts inside your head. That was why she was running. That was why she didn't stop until she was in so much pain, and had so little air in her lungs, that continuing would be as impossible as suddenly sprouting wings and flying to the moon.
When she could run no more, she collapsed onto a patch of grass beneath a tall Oak tree, and lay there for a while, gasping for breath, while the sun peered down at her between the leaves of the tree. As she lay there, her breathing slowly becoming more normal, all the thoughts she had been running from came rushing back into her mind. Flooding her brain like a river that has burst its banks.
Sighing deeply, she pulled herself up to a sitting position, and moved enough so that she was leaning back against the Oak's trunk. She had hoped the run would clear her mind. Or, perhaps, that some flash of insight would occur while she ran. But it seemed she hadn't had any luck with either of these. And now she was miles from home, and wondering if her legs would carry her back.