which is another way of saying
dont get crazy.
dont get hostile.
dont get flustered.
dont get your panties in a bunch.
dont get aroused.
Mandy: D.E.T. we can copy from one of the geeks Erika or Carla.
Cheryl: what if he finds out i wont graduate.
Mandy: for the last time D.E.T. if we cant copy we will just have nurse Dina sign us out sick.
Cheryl: damn mandy youve always got a plan.
A second usage, det is also short for and used to refer to a person or item that can detect; detector or detection.
* Purchase a det because they are building stealth units.