Well, at least how can she fear something without the illusion that she is in danger, but she could have wandered into one of those area's. What's to say something hasn't broken out...
Cages don't hold things forever, and then they need to be put back into the cage.
Somebody careless enough could have just have 'left' it unlocked.
Also, I do imagine the jungle, even to the best of extents, wouldn't be able to be contained and still have this 'wild' feel to it.
Now I retire to bed, and wait to see what you conjure up to scare her.