I need a 5 minute clip from a movie that shows a person losing his
temper in a business situation.

There's a great scene in "Office Space" in which several office
workers destroy a malfunctioning Xerox machine with a baseball bat.

Try "Fight Club" with Brad Pitt and Edward Norton. There is a scene
where Ed Norton beats himself up in his boss' office and then blames
it on the boss when security comes in.

This clip is only about 30 seconds long but its the first thing that
came to mind when I saw your question. Let me know if this works as an
answer.

http://www.wown.com/j_helmig/download/badday.mpg

tutuzdad-ga