Well... Better to lose an eye then to lose your life and lose the game of god yes???
Well his diary is the Investigation Diary, so maybe it tipped him off in some way? I really don't fully understand how each individual diary is going to work out.. But I still have this strange impression that he's a good person but will have to resort to violence against his former allies. Especially when the number of diary users weakens and soon enough, they are the only ones that have it.