Respectfully disagree, Foolestroupe (intriguing name BTW). I believe the word "berserk" comes to us from the days of the Vikings. Berserkers were Viking warriors who were overcome by a blood rage during battle and fought insanely with no thought of self-preservation.

There is an equivalent term from Indonesia - "amok".

"Gung ho" - is indeed "work together" so far as I know.
Sidelight: "kung fu", sometimes written as "gung fu" translates as "work done" or "accomplished man". (Chinese writing can be as much symbolic as literal, which accounts for the wide variation of apparent meanings in English.)