I was wondering why Mr. Bilra make his move with Alto-Hime
/Speculation mode ON
I'm not going into deep theories, but maybe the factor that activates the "ability" on Ranka is love, same reason why Sheryl can't do the same before. I said before because only in the Frontier Fleet she meets Alto-Hime at the same time with Ranka, and according Alto he heard both girls voices in the Vajra carrier back to ep 7.
So Mr. Train man realized this, and now that sheryl was "discarded" he is trying to get her under his control just in case the Galaxy Super Dimension Chat Room decides that Frontier is "expendable"
/Speculation mode OFF