Road flares work great to start a fire on a rainny day. They can also be used to distract people (People are just as dumb as bugs, light it throw it and watch them run to it all you have to do is find a dark spot to hide or shoot from. learned that one from Iraqis)
Not sure but i also read that some guys way out in the sticks managed to do some light welding with them not sure if i belive it tho.
As for heat strok you can buy heat tabs I live in Phoenix and work outside and take them every day with a lot of water. They work great and you dont get as tired as quick