If you were reading a mystery, several possibilities might occur to you. She might have found a dead body. Perhaps she has killed someone. Maybe she has discovered that someone hates her enough to kill her, and intends to do precisely that. A science fiction reader would draw the immediate conclusion that she has heavy mechanical legs.
Writers build stories out of details and subtleties and indirections.
Metaphors play an essential role in creating a world, an atmosphere, a context in which the action occurs. This is part of the mental model of the writer. The reader cannot share the writer's mental model, so the writer must adapt to the reader. In other words, a writer cannot construct an artifact that is independent of its context and usage. Metaphors provide a powerful way to communicate with the user, to link the mental models of the developer and the user.