You can do that and what you suppose is correct ; the sentences do correspond to one another, although not literally, but the “scenario” thing is possibly not of much interest here.

However, the use of the non negative expletive “ne” is not a necessity
. Personally, I see no difference in the register and if there is one it can’t be very important. Personally, I see no difference in the register and if there is one it can’t be very important, even in writing. Let’s try to make that clearer; what is called “langue soignée” in this article, is in my opinion yesterday’s “carefully written language” but today, in the particular case you mention, not using that after all useless word does not show slackened practices and as well, using it does not show for the time being a real concern for gratuitous stylistics; nevertheless the writing has to be quite formal or literary; in a simple letter to a close friend for instance, in which the style is akin to that of conversation I wouldn’t use it.