I can't really imagine what it would be like in war thankfully, and I am lucky to be born where I was. It is incredible how much of our lives come down to factors we have no chance to choose.
I train at a business level a similar kind of thinking as your sergeant, flexibility, adaptivity and the ability to do the job, regardless of the immediate conditions. In your case, lives depended on it.
Don't let me paint some glorious picture... I had a "friend" from Basic Training mysteriously show up with us in Germany. If I would have been smart then like I am now... I would have realized I was being set up...
That "friend" was a CID nark... (Central Intelligence Division)... he brought a joint into the room, and I figured...one hit...why not My goodness did that initiate a WHOLE new can of beans.. but regardless, I am still here today, for those choices, and the actions that were set in motion...
But as far as the flexibility, adaptivity, and what not... it honestly makes sense, AND makes things so much easier... whether it be in a job, or life...