You can use the turret of the RAT at the back of the garage to kill off the Titan guarding the Det-Pack. Make sure you check any Robot Control Consoles you find after the first robot you control is finished off. In the case of Titans, Elites, and the Predator in the I, Predator level, you will only get one Mil to control. However, usually in the case of Mil Grunts, the Mil will respawn, allowing you an infinite supply of controllable bots.