"'Hold on. What did she mean, "evidence"'" (108). At this point in the story, Kathy and Tommy are talking about what Miss Lucy said to Tommy about his art work. She called his art work "evidence." Evidence of what? I think that it has something to do with Madame and the gallery. Maybe it's evidence of the fact that they donors are real people. Or maybe Madame needs evidence to prove to herself something. I still don't see why she takes it in the first place if she is scared of the children. I think that Miss Lucy sees something different in Tommy, and wants to tell him as much as she can. But I think there are consequences if she told him. So instead, she seems to hit at things  like that gallery and donations. Maybe, more than anything, this "evidence" is for people on the outside, people who don't know everything that is going on behind the walls of Hailsham.