The soldiers are from different countries (I'm thinking US and UK) and different military branches.
Now my question is less about facts and more about, well, let's call it atmosphere or first hand experiences and this is why I find it very hard to google.
How do soldiers interact in a semi-official context? Like, it's not war territory, but it's also not entirely unofficial either.
Would officers, NCO's and enlisted men interact or would they keep mostly to themselves? Would rank be very important, like would it be 'Sir this' and 'Private that' all the time or would they actually start to call each other by their given names after a time? (This is very important to me, because right now my entire interaction feels very stiff and formal and I wonder if that's even realistic and if yes, if it stays like this and what would need to happen to change that.) Would it be possible to wear informal clothes at all or would it be military issue all the time?
What about an officer or NCO and a soldier from different branches or different countries - how would there interaction go? Would the officer/NCO still be authorized to issue directives even if it's a soldier from a different country or even a different branch? I read about the chain of command and thought yes, but than I read this (quote from an anonymous source from yahoo, so reliability is questionable: "<i>I have disregarded orders from an officer when an NCO in my chain has told me to, and I was correct. That NCO was exercising authority delegated to him by an officer who had command authority over me, the officer was not. I almost got in trouble for being too helpful to the officer."</i>) which confused me immensely.
I have a watched a lot of war or military series and movies (like Band of Brothers, Generation Kill, Black Hawk Down, etc.) and I read soldier's memories and wiki articles about different branches and their rivalries, but I'm still wondering about this particular scenario. Any help would be appreciated.