Although it had been a busy few years for Theodore, Draco was one person he hadn't lost touch with. Like Draco, he'd fallen out of touch with Blaise until recently, and hadn't really thought much of keeping up with people he'd never been close to, like Pansy.
He didn't dislike Pansy, though, and when he appeared behind her on the step - prompt, as usual - he offered her a smile. He was in time to see that she had knocked, and as such, didn't step forward to do it again.