FIRE is the second most important, critical, and essential element of surviving in the wild, because it's used for so many aspects of survival:
Warmth can be the difference between life and death. If it's super cold at night, or if you're wet and need to get dry, then there's potential for frostbite! A good fire can replace proper clothing and gear if you find yourself unprepared because you weren't expecting a true survival situation.
Fire repels bugs, critters, and creatures, because they sense it as a danger.
Hydration is vital, especially if you're sick or injured or are enduring high-intensity activities. Boiling water over fire provides a safe, effective means of purification. Water is another factor that can easily be the difference between life and death; if you drink contaminated water and end up sick or with diarrhea, you will actually be dehydrating yourself and will no longer be able to function or could even die.
If escape or exit is not possible (maybe due to injury), you can still gather materials to light a bonfire at an opportunistic moment for rescue, such as when a plane flies over or a boat comes. Fire can also be used for smoke signals.
This lighter is full of liquid gas. The fire is created by the spark from the flint--a circular metal file with little grooves on it. When you flick it with your thumb, friction creates a spark. If either component--gas or spark--is missing, you will not get flame.
The gas feeds the flame. Once it is lit, it will continue to burn as long as there is fuel. If the fire stops, you need another spark to ignite the gas again.