I don't think its glasses guy. He would have killed them already (unless he wanted to do some YOU'RE YOUR OWN BEAST) shit.
Punk man would be too obvious
Generic male protagonist would be a pretty good surprise, but that would be near impossible since he got knocked out.
Police girl - maybe? I'm not too sure about this yet.
Cripple girl might have done it, pretty unlikely though since she has a block through her chest.
Huge tits girl would probably be my best guess if the author knew what a plot twist was.