Back in the mid 80s the wife gave me a tool box for my Jeep. It's made from a hard resin material. Never seen a tool other than a can opener.
To this day it is packed with cans of food, seasonings, foil packs of Spam, Tuna, and a small box of crackers. Zip-lock bag of small packets of Mayonaise, Mustard, Pickles, and other condiments. Small boxes of raisens and dried fruit. Coleman Stove, extra fuel, can opener, hunting knife, plastic flatware, small plastic bottle containing emergency flares with launcher(smaller around than a soda bottle, and half as tall), zip-lock snack size bag of 30-06 shells, roll of orange trail marking tape, roll of Duct tape, and a small gun cleaning kit. After the weather turns cold I throw in a small box of Velveeta. My Coleman Stove has a metal storage box that I use to heat water. I never cook in this box, clean up is too hard. I take small tin foil loaf pans to cook in if needed.
The only thing I need to grab as I am leaving is a loaf of bread, which I snatch off the kitchen counter as I leave. After returning I empty and replace everything in the box so it is rotated.
When I do put cans of Spam in the box I always get the low sodium cans. I try and purchase low sodium cans of all canned good when possiable. I am a heart patient and I am always aware of sodium, and avoid it as much as possiable. With a lot of the canned foods I throw out the juice in the can, and wash the contents with clear water, before eating.
The advantage with canned foods is that it is precooked. It can be eaten cold. Every year it seems someone (grown men) will over heat an unvented can, and blow one up. I taught my boys early to vent the can before putting near the fire, or on top of the cabin stove. My oldest set a large can of Pork N Beans in the coals of the camp fire one year. Then walked down to the river to watch me land a Pike. We were walking back to the fire when the can blew. We were pelted with hot beans, and sauce. No one hurt, just made a mess.
This box is always packed and ready to go 24-7. When the mood strikes, or I recieve a call from a friend, I go. It's nice being retired, and having a wife that is willing to let you go anytime. My son laughs saying she is too ready, and always makes sure my Life Insurance is paid up.
As for water heater that overheat, in over 40 years as a Plumber/Pipefitter only seen one. Occupant replaced leaking temp/control relief valve, with a pipe plug. Heater blew at weld along the side low down near the bottom. Blew through closet wall into hallway, through second wall into living room, across living room taking out the sofa, large console TV, bookcase, a through the exterior wall. Hit a tree in the front yard sending it up over the house across the street. It landed in a back yard on the next street. Luckily no one was home when it blew, to be scalded, or killed. After seeing that hot water heater, a propane tank, and an air pressure tank, blow killing several people, I am scared when it comes to pressure tanks of any type. I have two Temp/pressure relief valves on my domestic hot water tank, and two on my Boiler at home. I won't trust just one, seen too many fail.