Exotic Hike to Cult Lake Movie

was on this exoctic hike with James and some other guy we knew but forgot who. Was thru like an amazon rain forest. We had to crouch around sleeping trees and under branches. Saw things like little toads and elves you could interact with like a video game. Then made it out to our destination which was this like young run cult thing in the middle of a clearing with a lake. Ran by some young charismatic male with black face paint lined down his face and long skinny hair. Like Derek bluestien  but not him. Some scenes were him building the place up. His number 2 changing. Then they build 2 huge "war" structures out of just plywood and were very flimsy. Then someone got a very high powered flame thrower and burnt one of them down. Then the last scene is me, Daniel Radcliffe, I think Julie Whitcomb, and the leader's number two, some guy, all walking into the lake. It's weird. It seems like they're playing but then julie gets a good chokehold with her legs on Daniel and is keeping him under for a good long time. I'm in the middle. Not sure what's going on. She's laughing but keeps him under. I see, it's them two who are the new powers and me and Daniel helped the old regime too much or something. Daniel's body flots up lifeless and I turn around and the guy is right there on me and Julie is coming. I go under, forced. But then I come out and I'm still there and so is David and everyone else and I think it's just a movie we were Filming the whole time! Next thing I know we're back at someone's house, like will Masterson's or something and chatting about the movie and his mom gives everyone a ride to I think the airport and I thank her for driving us safely there and she appreciates that