EDIT: As of June 2019, the requirements of this achievement have changed.
The original requirements were 'Breach and rappel through a window in "Consulate" in Casual/Ranked Multiplayer or Terrorist Hunt'
Now you can only achieve this in multiplayer, but on
any map instead of only 'Consulate'.
You can unlock this on any map where there is a building you can rappel on. Once on the attacking team, find a window you can breach and rappel inside.
Original Guide:You can do this quickly and easily by yourself in Terrorist Hunt.
First, press
on the main menu and click 'Options' and then into 'Multiplayer Preferences'.
Scroll down to the Terrorist Hunt game modes. Turn them all off except 'Terrorist hunt classic'. Then below that, turn off every terrorist hunt map except 'Consulate'. Press
to apply the changes.
Go back to the menu and into Terrorist Hunt. Click
and make sure 'Lone Wolf' is selected.
Start the game and make sure your character has breaching charges equipped.
Run up to the building and rappel onto the wall. Go to any undamaged window and stick your breach charge to it. Blow it up and then press
by default, to jump in the window.
Achievement should unlock a few seconds later.