He gave Jack a curious look, but listened as the Pumpkin King spoke of his creations. Dr. Finkelstein started to ponder what sort of potential flaw in the process caused [i]both[/i] Sally and Carver to try to flee -- their structures and methods were wildly different in nearly all aspects -- when Jack got to his clarification:

That the common variable was [i]himself[/i].

The doctor gave a small sneer. Impossible! He was also the common variable between all of his projects that worked [i]exactly[/i] as intended. He was particularly proud of Igor; he perhaps wouldn't have even conceived Sally if the hunchback hadn't been such a resounding success. His assistant was also perfectly happy to serve his original purpose. Clearly, [i]that[/i] couldn't be the problem.

...Actually there [i]was[/i] a common variable. Igor had been specifically created to be male. The other three, hadn't. Carver, of course, hadn't been intended to have a physical sex, and technically she still didn't, but she [i]did[/i] use feminine pronouns... That [i]might[/i] be the problem. 

He had created Jewel for the purpose of being a companion who could understand him on every intellectual level, something Igor never could and he wasn't certain Sally even tried to do. He knew his wife had least close to his intelligence, but there were a significant portion of conversations they had where she somehow couldn't fathom that he was simply [i]right[/i]. Perhaps none of them were strictly malfunctioning. Perhaps they were simply operating under parameters he had forgotten to take into account. 

"--failed to. She's their [i]friend[/i]..." The doctor looked up and realized Jack was still talking. He listened to the rest of Jack's speech, rubbing his chin thoughtfully. 

"He probably recognized that if she got into any more trouble, they wouldn't have access to her to pull their next stunt." Finkelstein commented. "It's been a long time since the hooligans had to put a plan into action that required only three of them. They [i]have[/i] been escalating their trouble since she joined their little gang... Hmmmmmmm... I suppose I could think of something to remedy the problem with her, though. Or at least get started on it..."