I'm starting to think that maybe we are reading too much into the video. Obviously it was released for a reason, but I think it's distracting us from the main issue: how did she get into the water tank and how long was she there?
After looking at all the photos on the board (thanks for posting, those were helpful), I doubt she made it up there alone. There are easier ways to commit suicide (including simply jumping off the roof if she had gotten up there) especially with someone who has access to psych meds.
What I truly want to know is what did she do while in LA? Did she post to Facebook that she was sightseeing? It looked like she did when she was in San Diego. When I travel, I tend to check out local restaurants and chat up bartenders, baristas, etc. Did anyone see her around the neighborhood other than the bookstore employee? If she was so outgoing, someone must have remembered talking to her. The hotel has free breakfast, did any of the other guests meet her?
So many unanswered questions to this case. I'm hoping someone comes forward with some information soon.