Understand that Mr Truss isn't supposed to be there and, in any event, he's from Queensland, so he doesn't have any power in the party room.
Barnaby Joyce was supposed to replace Mr Truss as leader of the parliamentary Nationals and Fiona Nash was supposed to become the deputy. However, the controversies that led to Arthur Sinodinos and Fiona Nash stepping back from Ministerial duties resulted in a set-back to those plans.
That's why Mr Truss is doing a very good impression of someone who's not in control of anything.