The World Series, game 2, had a LOT to do with that, though. The previous episode had a 1.6 which is decent(ish) for a Wednesday 10 pm show. By contrast the World Series (game 2) got 4.9 and drew about 17 million people.
Was the World Series still going at 10pm though? I don’t follow sports (and being in a different country I don’t have a clue) but according to all the ratings tables I’ve seen, the World Series wasn’t a competition in the 10pm slot.