Theory: Kabuto's failsafe
so, it seems that with izanami, itachi has kabuto caught up in a loop, UNLESS he decides his own destiny and makes the choice which itachi has set for him.
Itachi: I am the one who has your destiny in his hands, but you are the one who will decide it.
Now, Itachi's goal is to stop edo tensei. Meaning that the choice that Kabuto has to make is most probably to release edo tensei, upon which he will be freed from the loop.
As we all know, there aren't many edo tensei left; Dan,Kimimaro,Chiyo,Muu, and most importantly Madara. and also Itachi. Meaning that apart from Madara, the other tensei are no big loss, however Itachi will also be gone.
Now here's the thing, Dan,Kimimaro,Chiyo,Muu and Itachi, they were all summoned directly by Kabuto (too lazy to look for the manga page, but it can be seen from a couple of anime chapters ago).
However, Madara as Kabuto's special summon, was summoned by Muu, not Kabuto. And this is Kabuto's failsafe plan.
Even if you 'kill' the summoner, the summons, edo tensei, is unaffected. Kabuto's normal pawns will all be gone once he cancels edo tensei. BUT, Madara wasn't summoned by Kabuto. Furthermore, Muu will disintegrate also, meaning that there will be no way to stop Madara. And this is why Kabuto has Muu escaping from the guards. He's essentially the most important summon of all atm.
let me know what you think. Btw, the double-summon theory isn't originally my own, but Psukkar's, so if you like it, give thanks to him also. cheers