These individuals study End Times prophecy and believe that one of various scenarios might occur in their lifetime. While some Christians (and even people of other religions) believe that the Rapture will follow a period of Tribulation, others believe that the Rapture is imminent and will precede the Tribulation ("Pre-Trib Rapture"). There is a wide range of beliefs and attitudes in this group. They run the gamut from pacifist to armed camp, and from having no food stockpiles (leaving their sustenance up to God's providence) to storing decades' worth of food.
If you have a proper survival knife with you when the weather closes in you can make an emergency shelter; if there’s the material available to do so. But it’s better just to make sure that whenever you venture into the woods for any length of time that you have the right survival gear with you and the Sundome 2 Person backpacking tent from Coleman is that survival gear.
The stories of alcoholic beverages historically being safer to drink than unfermented ones are apocryphal at best; however, as any 17th-century sailor would tell you, the addition of some spirits to potable water that's been sitting around for too long will make it much more palatable. Liquor distillation was originally invented in part for medical purposes, and alcohol can be used as a solvent to dissolve medicinal herbs -- and also to knock out patients during good old-fashioned fallout-shelter surgery. High-proof alcohol can be used as an antiseptic, and it does a great job of cleaning wounds and preventing infection.
Some evangelical Christians hold to an interpretation of Bible prophecy known as the post-tribulation rapture, in which the world will have to go through a seven-year period of war and global dictatorship known as the "Great Tribulation". Jim McKeever helped popularize survival preparations among this branch of evangelical Christians with his 1978 book Christians Will Go Through the Tribulation, and How To Prepare For It.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!