Though you'll be there with training in mind, it wouldn't hurt to carry a life straw. You never know when you could run out of water. They are small and don't weigh anything. It will also be good should you not use it to give it away when you leave country or to barter with.
You'll be the face of our nation while there. Do us proud. If you see a fellow soldier acting like a fool, remind him/her who they are.