"Because it's my birthday," she told him in a manner as to indicate that he should have known that. "You proposed to me on your birthday, Sam, which meant that I had to wait to give you your gift. Anything I would have done after that would have felt-" She gave a small shrug and her eyes twinkled. "Less."
Truth be told, that proposal was one of the most beautiful things ever and she wasn't sure she was going to be over it any time soon. In fact, just thinking about it nearly derailed her thought processes, but then she was back on track.
"So, you know how much I love going home and I know how dizzying it is to take you there." She took a deep breath. "Also, sometimes I go there to hide and I shouldn't ever hide from you." She motioned toward the door next to his. "And this way, you can come find me or even escape yourself whenever you want. My home is your home, Sam."
So saying, she pulled open the door and let him peek in.