Do not use double wall to cook in. Not only is it extremely inefficient, but there are hazards, such as are mentioned previous.

When I am in the business of eating in a survival situation, nothing I would put in my single wall cup is gonna be there long enough to cool off much. As soon as the liquid cools enough for me to gulp, if such is the case, that is what I do. This is much different from camping, even with a backpack.

I can maybe understand titanium, but why stainless? It is heavy, and in a survival situation I would think aluminum would be preferable. I've primarily used aluminum cookware in my backpack trips all my life. Heck, even just aluminum foil would be suitable.

I guess a stainless cup isn't much to consider weightwise. Certainly it will be more durable than aluminum.