C-17 request for FCS MECH

Doing a favor for a friend writing a novel, and looking for a hand from any C-17 crew. Picture something killing your whole FCS (e.g. virus, EMP). How would you get to Mechanical override? Is it on the FCS panel, turning Pitch Tim MECH, Pitch EFCS FULL MECH, Roll EFCS FULL MECH, Yaw EFCS MECH? Or other master override? What would the callouts be for a RAF pilot (if it's different to USAF)? And can you describe how the control column would feel - e.g. heavy, sluggish?