Board Thread:False Info and Speculative Discussion/@comment-4772791-20160227092158/@comment-544940-20160301125209

Guy's you know the body in that tube or whatever it is, that's probably  Sébastien's body.

Because the Beast itself is getting more memories as it transform and the Dread Doctors could be getting impaitent as there time is limited((as stated in 5a episode 1)), they need to speed up the process so they decide to transfer the power/spirit of the Beast into that body which restores it to it's original form.