I haven't noticed a case where searching has returned a hit on only one of several words, OR where it's returned results where different words hit on different posts in the same thread.
I searched for "9mm 1911" and spot-checked a few results, and those words occurred in the same post.
I also just searched for "paragraph operator", which I think should hit this thread if what you claim is true, and this thread wasn't returned as a result. (well, it will hit this thread now, but pick two uncommon words in different posts and search)
Google, on the other hand, will return results with search words in different posts, because it indexes by thread (more accurately, per page... which means groups of about 25 posts).
“The egg hatched...” “...the egg hatched... and a hundred baby spiders came out...” (blade runner)
“Who are you?” “A friend. I'm here to prevent you from making a mistake.” “You have no idea what I'm doing here, friend.” “In specific terms, no, but I swore an oath to protect the world...” (continuum)
“It's a goal you won't understand until later. Your job is to make sure he doesn't achieve the goal.” (bsg)