User blog comment:Zathronas/Analysis by an author: Volume 2 episode 3/@comment-2006510-20140808072655/@comment-24218038-20140808121930

I agree with Penny's weight but I don't believe it would have mattered if she held on a little longer. You can clearly see Ruby immobilized after her semblance use. She needs a few second of recuperation to even move.

As for the feaqr/surprise. I don't believe so, Ruby has shown us more than once that she can act in surprising situation.