Mardet
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Mardet is a military abbreviation for marine detachment.
The mardet teams are likely marines trained in boarding any ship in the Fleet for crowd control or in the event of a takeover by forces internal or external to the Fleet.
Admiral Adama calls out a mardet alert team after the Hitei Kan, a tylium refinery ship in the Fleet, objects to the order to allow allied Cylons on their ship to make FTL modifications that could greatly extend its jump range (TRS: "A Disquiet Follows My Soul").