Dude...you still may be suffering from their brainwashing...
In fact, if forced back, I would probably be the biggest cancer seed they ever had. Every piece of literature would have a link to an apostate Web site. I would direct householders to apostate sites on return visits, ruining those calls forever. And I would tell people within the congregation that the reason why such sites are banned is that they tell the real truth. That would ruin that congregation, and probably plant more cancer seeds within it.
Cancer destroys things that are GOOD.
You're using an illustration that would put that kind of activity in a bad light. Yet the activity you are describing would be nothing short of HEROIC!
What your describing is more a Schindler's list adventure. Or Anne Frank, or any other good person that is stuck in a crummy situation who is fighting AGAINST THE REAL CANCER.
You are right when you say going out in the service could lead to ruining a life or even worse - killing that person.
Sad, but true.
I often get terribly guilty thoughts wondering if someone I witnessed to in the door to door work moved away but took the truth because of the seeds I had planted, and then they ended up dying for refusing a blood transfusion.
Wow.... it really is a horrible horrible religion when you meditate on it.