In "An Occurrence at Owl Creek Bridge," how does Bierce prepare the reader for the final outcome of the story?

The author
doesn't make clear whether Peyton Farquhar is dreaming that he escaped or if he really escaped,
but there are hints.  For example, I started to realize that the whole escape was a dream
sequence when Farquhar was able to avoid being shot by all the soldiers who were aiming at him. 
He succeeded in swimming away, without being killed. 

When Peyton Farquhar
is running, and running, and running, trying to make it to the safe part of the state, to get
home, he is tireless, he does not stop, after swimming, he is able to run, until finally he sees
his...