I've talked to so many JW's who really believe that as JW's they don't believe that only non JW's will be spared at Armageddon.
I've asked them if the preaching work is "urgent" and they say "Yes, we're living in the time of the end and it's a life saving message that we're spreading".
I've asked them what happens to those who don't listen to your message and become Jehovah's Witnesses. You see the light come on but they'll say "We leave it up to Jehovah to read people's hearts and decide".
If he's going to read people's hearts anyway, why the urgency?
If you really want to blow their minds, ask them how long it will take them to become perfect once Armageddon is over.
They'll tell you that it will happen gradually over the 1000 year reign of Christ.
Then ask them about the extremely elderly or someone who was diagnosed with a terminal illness before Armageddon broke out and was given 6 months to a year to live. If they are spared at Armageddon because they are righteous, how will they make it for a year let alone 1000 years. Will they die of old age or that terminal illness and be resurrected later?
Once again they'll tell you that Jehovah will see to it that these things are taken care of.
They spread their teachings as if they are base on indisputable facts but magical thinking is the order of the day when their logic doesn't add up.