Take a good look at this gals gait. In the 1st section, she is walking on relatively level ground and in the second part, the topography changes and the balance requirements become much greater. You may remember a post we did some time ago talking about proprioception and learning to walk here.
Besides the obvious gluteus medius weakness, genu valgum and pronation, R>L, can you see how when the task becomes more complex, that the system begins to break down? Did you see the increased base (wider) of gait? did you see the decreased speed of movement? Did you see the increased ancillary arm movements?
Keep your eyes open for clues like this in your clinical exam. When the going gets rough, the nervous system often reverts to what it knows best a slows down a bit.