Booker is a bit surprised by this... but he supposes you never really know a man until you give him a gun. It's a... more helpful reaction than how Elizabeth had dealt with her first murder, running off and refusing to speak to him for half an hour.

"You get used to it." he mumbles. At the very least, he'll live with it. But Booker gets the sense Adachi isn't going to hate living with it as much as he does. "Just don't lose your head - I'm not gonna last long if you go crazy."

Which is a lie.... he hopes.