Why did the woman eat the berries even though she was not sure whether they were poisonous?

M: Now let’s welcome Mrs. Green to our program!
W: Thank you.
M: So what’ s the story you want to share with us?
W: Well, it was an experience in a forest and I was lost. First I found some berries. I did not know what they were, or if they were good to eat or poisonous. However, I was so hungry that I had to eat something. Then while I was eating the berries, I remembered that when you are lost in the forest, you are supposed to look for a river, firstly because you need water to drink, and also because rivers lead out of the forest. So I set out to try to find a river.
M: But you could have been miles away from a river!
W: I was. I walked all day until I couldn’ t walk any more, but I found nothing. That evening, I realized that I might never find my way out. I might die in the forest and no one would ever find me.
M: Wow! You must have felt really lonely.
W: I did, but just as I was starting to feel really depressed, I saw a monkey sitting in a tree. He had come over to see what I was doing and he started chattering at me and leaping from branch to branch. That made me laugh. I decided at that moment that somehow I was going to survive.