Blackout (2009)

Synopsis: KM 31 director Rigoberto Castaneda takes the helm for this independent thriller concerning three people who become trapped in a hospital elevator for twenty-four hours. Her grandmother mere moments away from death, a young woman (Amber Tamblyn) races the ailing woman to the nearest hospital. Little does the concerned granddaughter realize that what first appeared to be a minor inconvenience is about to turn into something much more malevolent. Later, as the trapped trio grows increasingly frantic, a psychotic doctor (Aidan Gillen) reveals that he's more inclined to take lives than save them.     Source: RottenTomatoes.com