And would that be the end of the world? If you truly believe that those who die for Christ's sake are martyred and go straight to heaven, why would you value this life over the eternal Kingdom? Are we not to let go of earthly cares and not love the world? Or are those only empty words that sound good?
I wouldn't worry too much about those who stay behind. If you truly believe that God is merciful and just, then they too will receive what they deserved. Or do you doubt that?
This does not mean we need to commit suicide by letting others hunt us down like scared little rabbits. To the contrary! But as long as we understand that returning evil for evil will not get us any points in heaven. And this is rather a short pit-stop in eternity. So, long-term plans are probably wise.
The "just war" theory is a western distortion (actually an oxymoron, if you will) of the Christian mindset. Our Lord Jesus Chirst said "egw de legw umin mh antisthnai tw ponhrw"(Mat 5:39). Try to avoid him, and if you must defened yourself, do what is needed to survive, but not beyond.