McAllister is not Redjohn . He was forced to do this by him.
Just take a look at this scene : http://www.youtube.com/watch?v=ns_DWnqrEdI

Gun shot in the head doesnt fit redjohn ¨work¨ at all.
Jane doesnt have any emotions when he is face to face.
McAllister behavior was too weak , i think red john forced McAllister to do this
with the blake organisation. kill jane or lose everything

Heller is not stupid , that disapointement was intentional to finish stronger.