He really didn't mind showing her a few times. He liked helping her out (and letting her watch him work over his shoulder). He didn't notice where her eyes wandered. Instead, he was concentrating on the machine, carefully taking pieces out to reach the piece he was looking at.

"I said that the heating coils are the problem. They aren't heating up, so the liquid inside the air conditioner isn't evaporating." He pulled his hands out of the machine, absently sorting through the toolkit. "That probably means the compressor isn't compressing the gas properly. I'm going to take it out and see if there's anything clogging it."

It never occurred to him that his girlfriend, a doctor, might be able to recognize the subtle scars down his forearm for what they were.