Office Party

Office Party, also known as Hostile Takeover in some releases, is a Canadian thriller film directed by George Mihalka and released in 1988. An adaptation of Michael A. Gilbert's 1981 crime novel Office Party, the film stars David Warner as Eugene Brackin, a repressed accountant who suddenly takes three of his coworkers hostage with no apparent motive or demands.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.