In some universe there's an internal combustion shower powered entirely by an operator ripping out pull rings with their teeth and throwing armed grenades into a heating chamber.
Preferably yelling 'fire in the hole!' each time.
Preferably yelling 'fire in the hole!' each time.
Next, let's calculate the energy input required to heat a small cup of coffee and compare that to a hand grenade. (Hint: The coffee wins easily.) I wonder how many hand grenade equivalents a 10 minute lukewarm shower equates to?