In The Things They Carried, what are the parallels between the narrator in "On the Rainy River" and the boy he shoots in "The Man I Killed"?

I would want to argue that the main parallel between these
two characters is the way that they present soldiers as fully developed, sensitive human
individuals who share a similar distaste to the moral quagmire in which they find
themselves in and are just innocent youngsters, with their own lives, interests and
loves.

In "On the Rainy River," for example, the narrator
presents himself as a very tender young man in all of his emotional complexity. His
attempt to escape to Canada, and therefore avoid the draft, is explored in its fullness,
especially in the reasons we are given for him deciding in the end to stay and not cross
the border. Note how he explains his decision to
stay:

All
those eys on me--the town, the whole universe--and I couldn't risk the embarrassmet. It
was as if there were an audience to my life, that swirl of faces along the river, and in
my head I could hear people screaming at me. Traitor! they yelled. Turncoat! Pussy! I
felt myself blush. I couldn't tolerate it. I couldn't endure the mockery, or the
disgrace, or the patriotic ridicule. Even in my imagination, the shore just twenty yards
away, I couldn't make myself be brave. It had nothing to do with morality.
Embarrassment, that's all it
was.

Such descriptions
present us with the full emotional complexity of the narrator, and indicate how he is a
sensitive young man caught up in forces beyond his control that he feels he must comply
with.

In the same way, in "The Man I Killed," the narrator
creates a background for the life of the Vietnamese soldier that he kills, painting him
as another sensitive young man. Note the doubt that the narrator gives this soldier as
he grows up and how he finds himself unable to fight those who bully
him:

He could
not make himself fight them. He often wanted to, but he was afraid, and this increased
his shame. If he could not fight little boys, he thought, how could he ever become a
soldier and fight the Americans with their airplanes and helicopets and bombs? It did
not seems possible. In the presence of his father and uncles, he pretended to look
forward to doing his patriotic duty, which was also a privilege, but at night he prayed
with his mother that hte war might end soon. Beyond anything else, he was afraid of
disgracing himself and hterefore his family and
village.

Note the
similarities between these two characters. O'Brien seems to create a kind of double in
the life and background that he gives his victim. Above all, what motivates both of them
to be involved in the war is the fear of shame and embarrassment. Both are painted as
complex, sensitive characters that find themselves in a war that they are unsure about
but nevertheless feel obliged to participate in.