Street photography sometimes calls for really working a scene. I do this myself; different angles, compositions or even settings until either the scene dissipates or you get THE shot. Its probably like panning for gold; you sift through tons of rock for a few nuggets but those few nuggets make the process worth it. And your sergeant was right. I can’t even imagine being a photographer in your shoes then. Under such intense conditions the last thing you’d want to have to think about is “Did I get the shot?”, or “Should I press the shutter?” In comparison to the alternative, film was cheap. It may make a very interesting read to hear about your experience as a combat photographer.