Who says you only get to have one water bottle? My water goes in a different bottle (or hydration bladder) than my survival gear. The survival bottle could be pressed into use as a water holding implement during an emergency, but normally it's just a watertight container for survival gear. It does not hold my only survival gear. It supplements the PSK that is always in my pocket. But you can get a lot more survival gear into a Nalgene than into an Altoid tin, so the Nalgene stays in my pack.