I liked the last frame of the episode which might give us more insight into why they split up. The machine started looking at the partner as a possible thread. But I guess the machine is hackable for the partner, cause he knows how the machine works. The whole point of keeping the working of the machine secret was to make sure it wouldn't be abused. And the partner knows how the machine works so theoretically he could abuse it.
But the threat to decrease their payment for the machine was funny :-)