I remember a high school physics experiment that involved pouring diethyl ether in a spoon partially filled with water. Blow on it, and the ether eavaporates and chills the water to freezing. Just add ether to the FAK, and have ready access to ice for cold therapy, and to a fine general anesthetic for emergency surgery. Dandy little fire starter, useful for starting internal combustion engines, too. Surprising that more folks don't carry it.