Police can't say if the woman's disappearance, currently being investigated by homicide detectives, is drug related or what significance the video brings to suggest "foul play" is involved.
"She's acting weird in the video, maybe, but she might be playing with someone outside the elevator," L.A. policeman Christopher No said Thursday.
"We're just trying to find her."
He added the force has nearly exhausted tips since an initial public plea for information Feb. 6.
It's also unclear exactly when the video was taken as any time-stamps appear obscured. Police know the footage was shot inside the Cecil Hotel.
Lam arrived at the hotel Jan. 26 on her way north to Santa Cruz, Calif.
Family members are now in L.A. assisting detectives.
The video shows Lam for approximately two minutes and 30 seconds as the elevator door remains open despite her repeatedly pushing the console buttons.
Less than 30 seconds later after Lam goes off screen, the door closes and the empty elevator appears to proceed to lower floors.
Lam, 21, is known to rely on public transport, such as Amtrak and municipal buses. Police said she travelled to the U.S. for leisure purposes.
"Everything's a factor," No continued. "We're not leaving any stone unturned."