Running away
Nothing ruins your day like running into a hungry monster three times your size. Sometimes you just have to turn tail and get lost. Aside from the personal shame you might feel, there are no penalties for running away from a fight, that is, if you have a clear exit. If you have a free avenue for retreating, you can choose to flee on your turn. If your way is blocked, you'll have to mow through any opponents in the way of your escape. As noted in the Movement section, you can make a Gymnastics check to roll around, under, or over your opponents preventing you from running away.
Note that any opponents higher than you in the Reaction order will be aware of your intent to run away and could possibly move to intercept and prevent you from doing so.