Ikta is much smarter than Yatori. Substantially so. If they were playing chess, she thinks ahead four moves, he thinks ahead ten, while being blindfolded the whole time.

She's smart enough to see a few of the angles he's going for, when everyone else thinks he's doing something insane. She might not understand exactly what his plans are, but she knows enough to operate independently as his field commander.

Something like, "Yatori, obliterate their flank. Destroy their storehouses. [Then mesh with whatever we have going on when you rejoin the main battle in order to pincer them, or simply rejoin if they go to try to put out those fires.]"
He never says the latter part, she just does it based on the objectives he gives her.