Right now I stand still and cast rain or something rather than try to escape. That seems counter-intuitive.
What should be happening is they test to re-apply the status every turn that I am in a cloud or surface, but only proc the damage at the beginning of the turn. Thus if I stand in flames I risk burning indefinitely, but I won't die merely from trying to escape. I would even be okay with testing to apply the status again with each step (IE 20 steps through poison is 20 chances to get poisoned) which makes sense as well. Just once you are poisoned or burning you can't get more poisoned or burned.