The "htc" is obviously meaning the "high tender commander" ... a code for the "thc" ... "tender high commander"
The Machines will be burying the Aliens, using the Sewers as Hatcheries for the Invading Hordes, who will spew from Man Hole Covers during the Moomba Festival. Melbourne is in grave danger and I fear for You Joseph ... *manly hugz* ... who will I shop for Frocks with ... if You are Exterminated