My actions may not be "good" but they're not exactly "evil" either. It's more of a scientific approach. My "victims" would have to fit a particular set of guidelines for each experiment and each would be choosen for those varying traits. Their gender, race, social position, etc woud never figure into those experiments, except for rare instances. It would be weird for a man to die of ovian cancer for example, but that doesn't mean I wouldn't try it.
What's so interesting about it? You would kill me to further your plans, both of us know it. I don't suffer from Misa syndrome, and therefore see no reason to align myself with such a person. Your side would easily allow me more freedom to conduct my experiments and really wouldn't care to much about what or how I did it. The only real conflict, besides the threat of death, would be if one of my experiments came in conflict with your plans, i.e. I already wrote person X's name down, but you need to kill him now. Plus, while I know my actions really aren't "evil/good" the side of good will lable them as evil, so there you go. I'm more on your side of the fence simply because I know me, and if forced to choose...well I don't see me willingly giving everything up for some idea of good. Plus, lets face it...it's just plain more fun being bad.
And that's the dilemma. In this situation, given I would have the eyes, the chances of my being able to kill you are at 100% if we ever met. You know this. And you're right, it wouldn't matter if I wanted to kill you or not. After all, I could always change my mind somewhere down the road and decide to off you. You will do everything in your power to make sure someone with a notebook, especially someone with the eyes, can never find you. As interesting as I may make the game, so to speak, I don't see you actually sending me a spare notebook. I'm sure you would want too, just to see what would happen and how you might be able to use it to your advantage, but the risk is rather great. You would have to make sure it could never be traced back to you in any way, and doubly cautious if I would "join" the good guys in finding you. I may not tell them how I got the notebook but I would be looking for you. After all, if you did send me one, that would mean you would know who I am, quite possibly what I look like, and are therefore able to kill me at any time. Of course, I would know this and therefore would be at your disposable, under threat of death, to do whatever you wanted me too.
Congratulations. You just won. Not only did you get me on your side, but you placed me next to whoever was looking for you, since I would have done that anyway, and eliminated everyone in your way. The world is yours.
Of course...you do need that spare notebook first 
Did you ever look at a picture of yourself and see a stranger in the background? Makes you wonder how many strangers have a picture of you.