Sorry, this is going to be a novel. Been reading this for weeks and finally signed up. I have lots to say so please forgive me for the long post.
To me she looks frightened in the video. I'm 5'2 and weigh 110lbs. when in a spooked situation I often act like nope, I'm not worried, but inside my mind is racing looking for explanations. I wouldn't want to look more vulnerable if someone was watching and if I did see a hotel employee after being spooked, more then likely this would have put me a little at ease. My friends call this my Chihuahua attitude.
My actions would be very similar to hers if I was worried someone was hiding in the shower/toilet area of the hallway. (My understanding is that these rooms are just off to the side of the elevators and are often left partially open and unlocked)
I talk with my hands and tend to become more animated when I am anxious. I would walk with a quick pace but not race into an unknown area. The elevator starting to close then stopping would have freaked me out, especially if I started to hear some kind of noise in the hall and then no one was there. Would definitely think someone was hiding and be concerned about being cornered in the elevator or in the hall alone, specifically in this type of run down building with a not so great clientele renting rooms.
As for an explanation on why she was on a different floor then her own here are a couple of scenarios.
Just this past weekend I was on The Queen Mary in Long Beach, CA. At 2 o'clock in the morning I couldn't sleep and decided to explore the ship, but not the areas where the guests are allowed, the areas behind the scenes. The hidden doorways and old passageways that are no longer used by either staff or guests. In other words I went to areas of the ship that no one has been to in years. I climbed down rickety old ladders, explored the closed off sections of the old pool and touched the very bottom of the boat where there is sea water coming through. I was all over that boat and anything could have happened. Who's to say she wasn't intrigued by the dark history of the building and decided to do some exploring, caught someones attention and he/they decided she was an easy target, she noticed something wasn't feeling right but didn't freak out yet, just figured she would go down and then elevator incident happened or she may have noticed something wasn't right once she got in the elevator and things started going weird.
Maybe she was looking for an ice/soda/snack machine. Often they are on alternate floors in these dumpy hotels. Many time I have wondered around looking for soda machines and had to take an elevator to a different floor. I have even left my glasses on the nightstand thinking I'll only be a few minutes I can make it down the hall and back without a problem. Only to find myself 3 floors up going down the halls looking for the machine, finally giving up and just going back to the room.
-- the only problem I see with exploring the hotel is I need glasses badly, the bending to push the buttons make sense if you don't have your glasses or contacts and can't see well but I wouldn't roam a building without being able to see where I am going. Which could also heighten the amount of panic I am having if I think someone might be hiding but because I can't see well, I also can't see if maybe someone is peering from a partially open doorway.
Stepping to the left of the elevator if I think someone might be in a room to the right is something I would do also. To feel as though we have more distance between us. It means nothing in the long run but it would make me feel a little better at the moment to think they have to take those extra steps to get to me. Once the elevator wouldn't close I would assume someone pushed the button to the right and step in the opposite direction when exiting the elevator. The hand behind the head, could be she was putting her hand through her hair. I do this when I get nervous and would probably be thinking OK, am I letting my mind wander or is this real..
But here is another problem with someone hiding to the side. The floors in the hall are tile or marble, someone wearing shoes would make noise if they were scurrying around in a hurry. She would have heard that. I know if I did I would take off like a bat outta hell. Could be why she went back in the elevator and pushed the buttons more hurried the second time. Having realized they were detected the person steps out while she is still in the elevator and she has a conversation with him when she exits the elevator again. It looks like she is relieved to see someone and starts to explain what's happened with the elevator not working.
Unfortunately, the safest place for her was the elevator. Whoever she was talking to knew the elevator had a camera and wasn't going to go anywhere near it to avoid be caught on tape. Wish she would have called down to the front desk and asked a security guard to come up and walk her back to her room. Even if it was a hotel employee she was talking to it would send a red flag up knowing that there is a camera and that person isn't coming within view. No way in hell would I take the stairs alone after that.