@ ted: actually there is a point. i think the girl notices that she has no chance to win because the boy always has more creative ideas to deflect her weapons. then she wants to drop the bomb. (like in politics if there is no way to win because the opponents are smarter). but she realizes that this won't be the solution. so she gives up.

I think the end of the story is a bit confusing and leaves a lot of room for interpretation. but maybe not seeing the point of the story tells us that you're watching movies like a 6-yr-old.