In Duck, You Sucker (aka A Fist Full of Dynamite), John (played by James Coburn) has numerous flashbacks to his IRA days. In the final 15 minutes of the film, two seemingly important points are revealed:
First, that he shot his friend who had been beaten and revealed his identity to the British military.
This seems clear to me plot-wise, as it's tied to the revelations about Villega.
I do not understand the second (final) flashback, where it is shown that
the girl you see John with appears to be romantically involved with his friend as well when she stops kissing John and starts kissing his friend.
What is the meaning of this flashback?