For anyone annoyed by her "clumsiness" it's not easy to see roots coming up from the ground, large rocks, some kind of rise in the earth, large branches, or anything trippable when you're not used to the area or, you know, when there is already tons of crap that hides all that stuff even if you're looking. The other guys have been there often enough to remember, she hasn't.
Happens in real life as well, in exactly the way she did. You walk into a tree root because someone is walking next to you and you can't or don't step out of its way. That's normal.