After Gabby realized that his power though strong were not omnipotent. He could give suggestions to his victims. And his victims would act on his suggestions to some extent. But if he would model in doing something that they are not habitual of they would start realizing that something is wrong. And they would eventually get back to being their usual self.
With Gabby it made him realize that if they give him a suggestion from time and time and change the envoirment to such an extent that favors their suggestion then he could mold his victims any way he wants.
Fabian wanted to test his power a few more times. He wanted to test his powers with a wide range of subjects so he could know the full extent of his powers. But he didn't dare to go any further. While tempering with Gabby as well as with other test subjects he made sure that he wasn't found by anyone else. But still, he couldn't be too careful.
