To me, the elevator video looks like she is either talking to someone that just used or is going to use the shared shower/bathroom.
She's standing outside the elevator facing away - this shows a defensive posture, otherwise she would be facing the elevator. She's facing away from the elevator, because she wants to know if anyone is coming. The threat isn't that serious in her mind, it's equivalent to a "creeper", whom she's handled before.
So as she's facing away:
i) A person comes along to the right and is going to use the bathroom (check the map), and looks at her strangely, as in, "what is this girl doing standing there, facing away from an open elevator door?". She smiles embarrassingly, and says she can't see without her glasses, making "swimming gestures" showing that she's blind without them. She explains in points, using her fingers for emphasis what happened.
ii) She's talking to herself, with one eye looking out to see if the elevator door will close. She makes exaggerated hand movements while talking to herself (which some people do).
Here's a theory:
She meets a guy in the hotel, and becomes attracted to him. They go to the roof/14th/15th floor together, perhaps they have a few drinks, and he tries to make out with her. In doing so, she takes off her glasses. But when he tries to have sex with her, she refuses and runs off. She makes it to the 14th floor (if she was on the roof or 15th, she goes down one flight of stairs to lose him), and uses the elevator to go to her room. She presses the buttons to make sure he doesn't know which floor she's headed to. The reason it doesn't close is because she presses the Door Hold button by accident. (either by carelessness or drunkenness)
Someone comes from the washroom and looks at her strangely, and she explains to him/her that she can't see without her glasses, and tells him/her something, using her fingers for emphasis. She then resigns, and decides to go back to where the guy was (possibly the roof), to get her belongings back. She meets her end.
This is one theory that would explain: i) why she was on the 14th floor in the first place ii) her movements in the elevator iii) how she ended up on the roof without the need for someone to carry her body