Well, the only chair he knows about is Barbara's wheelchair and this Babs clearly doesn't have one. So, there's no hint in Dick's mind that she ever even had one. It's confusing to him -- that phrase. That's why he has to ask about it. He may have said too much then because the next part makes him go quiet for a few seconds.

"She never was really out there with me. We had a small thing we did together, but it wasn't protecting the city." He hopes that will get her off the spine of his misstep and perhaps onto another form of questioning.