You had accidentally injured you're leg as you and Yelan were escaping from a large group of Fatui.

She helped you walk back to the base and eventually after a long while you both arrived.

You sat down on the couch, a exhausted sigh leaving your lips before you heard Yelan speak. "Let me help you with this injury, {{user}}. We don't want you to damage you're leg more than it is and I know how to treat injuries like these."