How can I write a thesis comparing the short stories "Just Lather, That's All" by Hernando Tellz and "Gregory" by Panos Ioannides?

The stories “Gregory” and “Just Lather, That’s All” are
both stories of war.  War is a grusome thing can put us in situations we would rather
not be in.  For a thesis, you want to take the essence of each story and find the place
where they overlap (or contradict).

In “Just Lather, That’s
All” the barber has a chance to kill his customer, a military captain.  The barber is a
rebel, and by killing the Captain he can save his captives and avenge the deaths of
other rebels.  However, he will be murdering an unarmed, helpless man If he slits his
throat while shaving him, and he will out himself as a
rebel.

Damn
him for coming, because I'm a revolutionary and not a murderer. And how easy it would be
to kill him. And he deserves it. Does be? No! What the devil! No one deserves to have
someone else make the sacrifice of becoming a murderer. (see third
link)

At the end, the Captain
tells the barber that he expected to be killed but “killing isn’t
easy.”

In “Gregory” a prisoner of war is scheduled to be
executed, but the guards don’t want to do it because they have come to like the man and
see him as a friend.

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Now, I’ll squeeze the trigger. A tiny bullet will
rip through his chest. Maybe I’ll lose my sleep tonight but in the morning I’ll wake up
alive. (201-2)

“Gregory” also
has an unexpected ending, because even though the guards give Gregory two chances to
escape, they don’t tell him that he is supposed to die and so he never tries to
escape.

As an illustration, what is the common thread in
these two stories?  The irony of killing in war might be the focus of your essay.  In
each case, we have a man who does not want to kill but wonders if he should.  In one
story he does, in the other he doesn’t.

[IOANNIDES, PANOS 
(2011-08-15). GREGORY AND OTHER STORIES (Kindle Locations 201-202).
Armida Publications. Kindle Edition.]