Tomorrow we may all be dead, but how would that be different from any other day? The bible talks about a spiritual warfare, and we all are, like it or not, recipients of that warfare . Death can come for us at any time, in any place.
Now consider the alternative. What if they are right? What if the all the prophecies are true? What if tomorrow Armageddon will begin to come? Isn't that worth fighting for? Isn't that worth dying for?