Im still with you guys, seriously pretty much only things can be blamed would be Shinichiro`s own blindness, Shinichiro`s friend cowardiness to face the truth and well, the deal the Noe`s brother made with the Shinichiro.
So in short:
Shinichiro = Blindfolded monkey with an pistol, just shot himself to leg.
Ai = Afraid of unknown consequences, tryed not to hurt anyone, but didnt have the courage to face the consequences, and face the Shinichiro before the shitstorm began.
Noe`s brother = Well, he is just doing he`s part of the job.
Noe = Doing good, getting closer with blindfolded monkey.
Shinichiro`s friend = Isnt blindfolded, but doesnt have the courage to face the truth. Coward.