User blog comment:SpookyBoogie27/Light Novel Spoilers/@comment-67.176.158.104-20140207023318/@comment-1359322-20140207043747

Breakdown the Beast functions in the same way as the Juggernaut Drive, the possessor would be in a state where you can't reach them at all. In the Vritra Promotion, Saji's will is still maintain and you can still talk to him, he just doesn't have full control of Vritra's power so it goes berserk.

This is actually like the Juggernaut Drivesituation. In Volume 5, Ishibumi wrote that Juggernaut Drive is a form exclusive to SG with beings sealed in it. In Volume 11, he changed to it being exclusive to the BG & DD and created Breakdown the Beast for other SGs.

In Volume 7, Ishibumi said the four SGs combined, but then he decides to retain 4 SGs and created the Vritra Promotion instead.