Grey is not exactly known for being the most stable of people either, as we see him often entering bad relationships (and that he thinks with his dick). He knows that it is bad, but does it anyways. Not to mention, Ken's route seems to be different from Mark or Gabe in the type of horror that it is portraying. I can only see Ken's route ending in tragedy, as I do not see anywhere that he will be able to escape the his past actions, but perhaps he can redeem himself before he meets his end.