He has a couple mentors such as his mom, priest and little brother. They all help convince him to volunteer and give him reasons why he should. when he crosses the threshold, Chris becomes his mentor.
He crosses the threshold when he goes to his boss and takes the assignment. He is then briefed and trained a little bit then dropped by helicopter into no mans land. All alone. The point of no return.
Test, allies, enemies. He has many tests, like surviving in no mans land, capturing film, escaping the scout parties, and the animals. His allies that helps him is chris. his enemies are the animals and the scout parties.