This can be done in the Centre Hospitalier singleplayer mission (make sure you are by yourself), as it is the first mission with a wrench. The wrench can be used to knock anyone out, as well as instantly complete an actionable icon regardless of the character (i.e. lockpick, computer hack, etc.).
Any character can be used (I used Gentleman and wasn't even spotted - not needed for the achievement), just make sure you don't switch to the crossbow later in the level. When you climb in the helicopter after switching to the hacker, the achievement will unlock.
I can confirm this works in Enhanced and Classic mode (I don't know if it works in Zombie).