She willing volunteers to serve for the army and give her contribution to the country. As she changed her name from Emma to Edmond's she also changed the way she looked. She cut short her hair and wore male clothes to represent as a male and decided to take part in the war.
She wanted to fight and show her skills and being a woman it didn't stop her from being what she wants to be and do what she feels like doing for the nation and the society. She was misunderstood by the troops as a male and was given a chance in the war.