I suspected that might have been your thought process with the hatchet. My choice would be a knife with a glass breaker tip on the pommel end. There are good quality fixed blade and folding knives that fill this need. Less weight and multipurpose if you have to walk away from your vehicle. I think a crowbar or wrecking bar in your truck would do a better job of emergency vehicle entry. You wouldn't bring it with you if you were on foot.
Foil isn't going to cut it for cooking. Foil makes a good re-usable wind screen for a stove, but you wouldn't get many uses out of it cooking. Even the heavy duty foil would be susceptible to burning through. How would you hold it while cooking? How would you clean it? Nah, get a real cup. A GSI cup costs less than $10 and fits on the bottom of a 1L Nalgene bottle. A canteen cup costs $6. Cheap cooking vessels.