She steals luck, and obviously she doesn't care about whether she cheats or not.

[Dave fails at comfort, woe.]

But you can't protect me forever. And the last thing I wanna see is you dyin' 'cause I tumbled head first into the gapin' maw of trouble, and possibly stupidity.

[He's trying to stay realistic, since when he goes back, Bro won't be there to help him.]