Yeah, it's confusing.
That question isn't attached to any game/setup; it's just showing a type of question stem and pointing out a little piece of logic "only bother checking the people who VARY among the remaining answers".
You can tell it has nothing to do with the previous page's relative ordering tree in part because Q is in these answers, but wasn't in that tree.
Also, O could definitely be 3rd, so we wouldn't have crossed out all the answer choices with O in it.
So ... not a typo, because it's not related to the previous page's diagram, but you thinking it was is completely understandable.
p.s. in case you have future "is this a typo questions", there is an actual Errata page
https://www.manhattanprep.com/lsat/errata/If you see a potential problem that isn't there, please let us know!