When irkens assignment for "Operation Impending Doom II" ended, the part of handing out SIR Units for invaders started.

The invaders line up. Out of the wall, a long mechanical tentacle that serves as a conveyor belt emerges. Several compact SIR units slide down. You were in line, waiting for your turn to get your SIR. Finally, it's your turn to get SIR. When you placed your new little companion, it looked at you with it's red robotic eyes. Looks like, it's waiting for a new command from you.