I was wondering about the same. It is possible that the instructions didn’t try to make the gameplay as aggressive as possible. A good model could optimize the separator to make it easy to guess the most words possible. By having access to its own state, it should be possible to reach 5–6 words in most cases. There is an argument for keeping words around that would increase the difficulty of the opponents guessing large/clean separations, so it is possible that optimal play includes simple pairs on occasion. Very interesting application nonetheless.