The Final Scene
I chose to take a closer look at the final scene, from the point that Ethan (John Wayne) swoops Debbie up into his arms and says "Lets go home." This idea of 'home' was what struck a chord with me as I questioned whether Ethan really had a home. His brother welcomed him into his home at the beginning of the film but he was always awkward and on the move, as if ready to take off into the wilderness he had been roaming before his return.
There is an almost cyclical narrative to the film as the end shot shows him turning around and walking towards the wilderness, the place he seemed to find the most comfort in as he knew how the wilderness worked - civilisation seemed to be rather difficult. Ethan seemed to come alive in the wilderness with something to search for, and when that searching is over he feels he still cannot return to civilisation. This could be put down to guilt, perhaps, as he was originally going to try and kill Debbie, or it could be a belief that he could not survive in the world of civilisation as he himself had become one with the wilderness, much like the Indians. The latter option seems more likely on account of his ideas of racism and his realisation that he is more like the people he hates than he first realised.
The door is one of the biggest motifs in the film and its part in the final scene only acted to make it all the more important. Everything can change a few steps inside the door and a few steps outside, there are no real boundaries from the inside civilisation and the outside savage wilderness. Evidently Ethan feels that he is just not ready for the civilisation of the world, and retreats to the savage wilderness that he feels he knows best.