Selina accepts the hand mainly because she can't think of a reason not to do it. The multiple layers of shock are still sitting heavily on her shoulders. Harvey isn't the Two-Face she knew any longer and he isn't exactly harvey any more but some odd combination of them both. It adds a level of melancholy to everything, which brings the total number of emotions she's feeling now to far too many.

"You didn't owe me this."

She's looking for Eddie and Bruce. There is so much blood - on her and on the floor.