Board Thread:Episode Discussion/@comment-34633327-20180105193053/@comment-26403517-20180108175930

Cinder stole only half of Amber's power because she was inturrupted by Qrow. Even so, that left Amber in a permanent coma. If Cinder didn't get interrupted, Amber would have died then and there.

And Cinder trying to steal the power of more than 1 Maiden is a part of the plot, so therefore I don't believe there would be no plot.