There's another consideration, too.
Sure, they'd (theoretically) escape secular justice, but the scenario you've described would absolutely have to be maintained...
...indefinitely and using increasingly draconian means...
...simply because no hint of their self-imposed exile could be allowed to be publicly exposed.
Doing so would reveal that...
a) ...they're cowards for hiding, instead of bravely defending their convictions the way Jesus' apostles did, and...
b) ...they're egregiously deceitful for letting the rank-and-file think they'd been "raptured" away...
...and both would too deeply undermine the Org's claims of authority and exclusivity, which can never be permitted.
No matter how comfortable they'd be, it would amount to a life sentence.