Kei's courageous attempt to escape led to him finding out that he essentially has superpowers in his current state and despite him getting caught by that monster anyway, his bravery encouraged Kato to do his best to help him out.
So he is going to find out that he is super strong all of a sudden? I kind of thought it would occur to him mid jump ... and did that girl really just die? I really thought she would be around for awhile longer but oh well.