I love the character development in Mugai. Though in this situation Yukimura's predictions are questionable, because Mugai can't cover both sides anyway, so him going to either east or west doesn't change that much, since the other side is free to advance. Not to mention that since Yukimura isn't held back by Mugai anymore, now he can join the northern battlefield, and there isn't anybody there who can stop him, so in a long term Mugai going somewhere else simply means that instead of a pincer from west and east there will be a pincer from east and north after Yukimura beats everyone.
Of course, there will be some reinforcements incoming soon, the paper boy is nowhere to be seen so far, the guys from the training in the mountains, maybe Mushikari will come to help, but neither Yukimura nor Mugai should be aware of that when making decisions in this chapter.