[Honestly, he knows her way too well to be surprised at her reaction. She's more stubborn than him in many ways and unlike someone else--she never has issues showing that side of herself to him. Which he tends to believe is one of the positives about their relationship. Though they both have tended to lie about feelings and emotions in the past, they've never been afraid to show the other their bad sides. It just has the downside of them being more willing to hurt each other more.
She's upset about what he said, Zero knows that's from where the defensiveness is coming. He also knows she wants to believe her words and prove him wrong.Even if he has doubts, she's still adorable as she gets all offended at his take on their relationship.
He's not upset, because the words he told her were his reality and cross to bear. It's up to him to give Yuuki a reason to stay with him that was stronger than her reason to leave. Something he'd never tried before.
But speaking of leaving...Yuuki continued to hightail it toward the door.
Oh. He's not worried about that at all. She'll be back.
And he can't wait to see what sort of face she makes when she realizes the bots won't let her leave. Or how she'll try to avoid him.
Watching the show, Zero waits with his back against the wall for her to get stopped.]