Notice first that xer name is Eve. Her directive, her task, her reason for being is to put life inside of her. As soon as Wall-E finds the plant and shows it to her, she puts it into her torso and immediately shuts down. As soon as the life is inside of her, she becomes an object whose only worth comes from how well she protects the life inside. Her purpose has been fulfilled. She no longer has any agency until she “delivers” the life form when and where she is told according to the directive.