‘He wrote his parents about how hot and boring it was but he was thankful his office had air conditioning.”
That can be a very true statement, having worked in an air conditioned office, being bored etc. Working in an office, or being a REMF, did not exclude one from combat. There were many ways for a REMF to get wounded during a mortar attack or ground assault such as being on the perimeter or just running to your bunker.
I doubt he was in an office. It was just a story to make his mother feel better until he could make sure he wasn’t going back.