During the first level, enable the /impulse 101 code and go to either one of the two security officers (Barneys) guarding an area. Use the /impulse 76 code to spawn a Grunt near them. Do not spawn the Grunt in a wall or Barney or the game will end with an error message. Kill the Grunt quickly and leave it on the floor for a couple seconds. Barney should say "Ew, what's that stench?" or something similar.