Just months before undertaking the most forbidding journey in his life as a young missionary to a remote Indian Ocean island, John Allen Chau was blindfolded and dropped off on a dirt road in a remote part of Kansas. After a long walk, he found a mock village in the woods inhabited by missionaries dressed in odd thrift-store clothes, pretending not to understand a word he said. His role was to preach the gospel. The others were supposed to be physically aggressive. Some came at him with fake spears, speaking gibberish. It was part of an intensive and somewhat secretive three-week missionary training camp. Mary Ho, the international executive leader for All Nations, the organization that ran the training, said, “John was one of the best participants in this experience that we have ever had.” For Chau, 26, the boot camp was the culmination of years of meticulous planning that involved linguistics training and studying to become an emergency medical technician, as well as forgoing full-time jobs so he could travel and toughen himself up. He did it all with the single-minded goal of breaking through to the people of North Sentinel Island, a remote outpost of hunters and gatherers…