A Missionary, A helicopter will only go so far, it's really dense jungle there, you gotta go on foot for weeks at a time.
hopefully I would like to preach to the newly contacted tribes there, that have never heard about the Gospel.
I wont go to the non contacted ones(first contact is never good, hostile natives, our diseases would kill them etc.)
but there are a few that have had recent contact with the outside world. those are safer, for them and for us.
and to get to them you gotta go through the jungle.