Cognitive dissonance. They (most hardcore ones that is) have some form of this belief embedded deep in their indoctrinated brain, while at the same time go about their lives pretty much like the rest of the world around them.
I remember my F-I-L in the course of 5 minutes going from how 'the end' would be here between 5 - 10 years to talking about how he was going to spend his retirement.