Because, answers the version of himself in his memories, locked away and buried, I've seen the same thing happen to Professor Rammsteiner. I know what the results of your methods look like.

I just don't understand why you felt the need to do this sort of thing to me.

On some level, Jade still doesn't understand. But mostly, he just regrets having ever brought up that topic, although he can't tell if that regret is something he actually feels or something artificial, imposed on him by Professor Eichel.