"Here's what we're going to do: I am going to go pay for lunch, walk out of here, and then we'll meet at work, sometimes talk, maybe about nothing, and we'll see if we can't manage to be acquaintances before we're friends. What do you say to that?" While Sebastian may wield his ugly history as a weapon, he doesn't trust people easily. It's fair to say that he appreciates Martha's situation, but that he is not compelled to shoehorn a new friendship into his life.