The suggestion makes the Doctor feel ill; Sigma takes a deep breath to calm himself. Allowing the Capitol to modify his body would certainly look good, but he isn't certain he could handle it, mentally or physically. Surgery terrified him. The idea of any sort of knife touching his skin terrified him. At the very least, it would mean another week at least of helplessness while he recovered... he could feel revulsion in his bones.

"...That might be a better plan. I will think on it," he lies.

It may have been wise to voice his concerns or to bring up the terror another touching his cybernetics gave him, but foolishly, Sigma stays quiet. He is supposed to maintain the illusion of strength, even in private. "I believe that's everything," he decides.