It's funny people are saying Kakashi's stupid for not using chidori inside Kamui. It will kill the plot. Rin's death should be uncovered and Kakashi and Obito exchange dramatic moments cannot be discarded. Also you should consider Obito transforming into a good guy and helping out in beating Madara's ass once and for all. We'll never know.
Soooo stop saying Kakashi's stupid. Enjoy the moment. Liver blow and hook in the face is enough for now.
Shit's bout to happen
Not a Kakashi Fan though.