It is something he's familiar with, but she starts talking about lasers and he knows that's not going to fix what's happened, he knows no matter what, he's going to feel the loss of Finch from Darrow, but he can't pretend as if the weapons Dutch is talking about aren't interesting to him. And it will distract him, too, which is the sort of thing that he knows will be helpful now.

It'll keep him from slipping away. From drinking like he used to.

"That sounds like science fiction," he says, then laughs a little. "Which is what someone from my world would have said about my life if they knew the truth about the Machine."