Do you really think those who stay behind have a chance of survival against the big bad guy?

think about all the elements against you if you stayed:

Computers, satellite targeting, thermal vision, tracking devices (Cellphone, etc), civilian anti- religious mobs, army and military equipment, trained K-9s, sonar, Voice ID, detectives, Facial identification, Fliers, NO FOOD, NO WATER, NO BUYING, plagues, flu and sickness, no medicines, wild animals, reptiles, and insects, etc.

Nature will most likely be deteriorating and easily will be a “Day after tomorrow” meets “I am Legend” scenario…

Put in thought that a human can only last about 1 week without food and water and you will most likely be alone.

Really you think ANYONE has a chance of surviving until the next chapter?
they will be fighting for survival actually
By the way all those weapons i mentioned are very real.. pick up a military and science today magazine before speaking please..