Want to Share A recent Discussion I had about Full Metal Jacket

So I was at work and we were talking about the ending of the Full Metal Jacket and my boss says

It's crazy that the hooker was the sniper at the end.

My mind goes kinda haywire at this comment. I'm reflecting on it, and I say.

I don't think they were the same actress or character.

And he tells me it is the hooker that's why they're all in shock at the end of the film and thus the audience is shocked as well.

He was dead set on his analysis and I wouldn't budge either and presented that the actresses are different and that the point of the sniper, as a child was to show the futility of the conflict and everything they were there for.

He relented at that point.

I'm not sure what that says about my boss, or how he was confused by the ending. Has anyone else come across this when discussing the film with others?