My thought on the mystrious lense is that it supresses Al's talent. Al the first said that breaking was the worst thing ever, yes? So then if he was able to create a lense that supressed the talent he might think he was saving other people from the horror. I mean, that also explains why only those with the breaking talent would want it.
Also, I can almost promise that Al's going to break Bastille so she gets a talent. In the first book there was like two things that he said would never happen -- the "super powerful lense getting blasted" which it does (he then follows up with "that's an accadent and will never happen again, which it does) and Bastille getting a talent. Every time he said that though it ended up happening, so Al's either going to marry Bastille or else he's going to break her. (I could see him breaking her having to do with the big huge problem thing.)
Also, miyabi -- "She was dead. Dead dead dead dead dead." *giggles* Good times, good times.