This case was a bit complicated to handle. however, as of now, since she couldn't find any means to proof that she was indeed capable of performing the deed, Estelle wanted to seek a willing patient that would agree to her operation. She was sure that if there was someone out there who was less capable of getting treatment, much less than Theo and Tertia, then they would be easier to convince.
Although this was a backhanded statement that wasn't too pleasing from a moral standpoint, this was Estelle's first large exploration in Vaitral. She saw that Theo was indeed a smart child, and had an instinct that he was hiding something behind all his words. When he talked about the dragon that caused Tertia harm, he made a lot of pauses that led Estelle to believe that the matter was not as simple as Theo offending this dragon just through simple means.