This link from Allen West tells it all. "McConnell said the 55-year-old was shot after charging at police officers who were standing at a roadblock. " http://www.allenbwest.com/2016/01/watch-militia-man-present-at-oregon-sh... (link is external)
I don't know any of the people involved but by watching Finicums' behavior during the interview it appears extremely unlikely that someone being threatened by the actors in police uniform would actually charge at them.