Entering the ATMOS factory with other UNIT troops during their raid of the complex, Private Steve Gray and he discovered a cloning pool in the building's basement. The Sontaran General Staal commended him for his leadership skills. Staal hypnotised the two troopers and had them capture Martha Jones so the Sontarans could make a clone of her. While hypnotised, they regarded Staal as their commanding officer and considered it their duty to obey Sontaran commands.