Although there's a definite tension when Stark steps forward to touch the arm, it's not exactly unexpected and so he keeps himself still. He just hopes that when this gets further into repairs that he'll still be capable of keeping a lid on his many issues with being worked on.

"It's been removed before, but it's connected to the nerves so it was done with a doctor as well as engineers."

Not because they wanted to make sure he had been well cared for, there had never been anything unnecessary like anaesthetic, but because the Asset was too valuable to risk permanently damaging.

"Can you fix it?" No, probably the wrong question... "Will you fix it?"