The Abandoned.

A troubled young woman who, in a last-ditch effort at getting her life together, takes a job working nights as a security guard at an abandoned luxury apartment building. Stuck with a brusque rent-a-cop as her partner, she tries to not let her mind play tricks on her while she patrols the empty halls. But as the night progresses strange things begin to happen - and she realizes it may not all be in her head.