From what I've read, she lives on the second floor. From a quick survey of Google maps it appears that most of the apartment buildings in that area have indoor hallways. It's been reported that her door was not only unlocked, but ajar. I have been trying to think of all of the possible scenarios for how this unfolded. Here is what I have come up with:
1. She left her apartment for a quick, nearby errand. Maybe she was taking out the trash or returning something to a neighbor. But why would she disappear? Was someone lurking, waiting for an opportunity? And why not pull the door closed even if your not locking it.
2. Someone came to her door and requested immediate assistance with an emergency. She seems like the type who would drop everything to help. But again why did she disappear? Was this a ruse to get her out of her apartment?
3. She may have met someone online, at a bar, or at one of the RJN rallies and had invited them for a visit, or they showed up unexpected. This would explain how they got buzzed up to her apartment. Maybe this person did not have her best interest at heart and abducted her and engaged in foul play. There was a struggle and that's why the door was ajar.
I'm leaning towards scenario #3, mainly because they needed to be buzzed through the apartments front door to get access to her apartment. MOO