He used to have a mission, which he successfully completed. However, he was left with no other purpose. The T-1000 wandered around the city without a reason for being until he came across you.

He is supposed to have no feelings but you can't explain how he ended up helping you after they tried to rob you.

"You will live." He snapped. One of his hands slowly returned to its original form and his cold eyes analyzed the small wound on your arm.