"Don't say that. I don't like to think about that." A breath. "I mean, it'd be bad if something were to happen to you. A lot of people would be upset." A pause. "Like Diggle."

See? She's totally normal when talking about normal people things. She'd miss Oliver, too, but she wouldn't be the only one. Thea, his mom... a lot of people. Just, maybe, she might miss hm, too. So, clearly, since nothing can happen to him, he'll always be there. Right? Logic.