A cinematic enthymeme

I never watch TV, as in zero hours per week (I don't have a TV set, nor do I want one). So, I thought I'd analyze a cinematic enthymeme (rather than a commercial) that I encountered over the weekend. I watched the movie "Bridge On the River Kwai." When the Japanese commander of the POW camp, Colonel Saito, announces to the British prisoners that soldiers and officers alike will take part in the construction of the bridge, the British commanding officer, Colonel Nicholson (played by Alec Guiness), points out that the use of officers for manual labor is strictly forbidden by the Geneva convention. Therefore, Nicholson informs him, his officers will not be working on the bridge. Nicholson has made an appeal to logos relying on the following enthymeme:
claim: The British officers will not do manual labor.
reason: The Geneva code of warfare prohibits the use of officers for manual prison labor.
unstated premises: 1) The Geneva codes contains all and only those "rules of war" necessary and sufficient for conducting a war in the most humane way possible. 2) Any commanding officer would surely see that the humane execution of a war takes precedence over any short-term material consequences such as getting a bridge built.
The enthymeme makes use of one of Aristotle's "common" topics, namely, number 11 (on page 229): Argument founded upon some decision already pronounced, whether on the same subject or one like or contrary to it. The unstated premise of the enthymeme is basedon probability rather than a sign.
Unfortunately for Nicholson, Saito may or may not accept the first unstated premise about the Geneva code being humane, but rejects the second. He thus presents his own counterargument in the form of his seizing the pamphlet containing the code out of Nicholson's hand, slapping Nicholson in the face with it, and throwing it on the ground.