Hell yeah he's protective. Little shiny thing like that, she needs protecting. Plenty of big bad men out there in the black looking to take a thing like her, make her do any gorram thing they want and not pay any attention to what they got. He's not saying he's not a bad man, and he's certainly not saying he's not proud of what he does. He likes his job and his life. But he knows that someone like her is special, and if you have 'em, you shouldn't let other people take 'em. Little doctor man just walks onto Serenity and starts putting the charms on her, of course he's gonna bristle. She's too special for the fancy inner-planet likes of him.

And it's not like she's innocent or nothing. He's heard the stories of how she got on this ship, and he knows she's a real woman, with needs and passions and all that whatnot. She doesn't pull any of that prissy, too good for a working man gos se, like some females he could mention. She's certainly not afraid to get dirty. He's spent plenty of time in his bunk, imagining undoing one of those jumpsuits of hers and taking her right there in the engine room, putting his big hands all over her tiny body. He'd hold her tight, keep her safe in his big arms, beat the stuffing out of anyone tried to mess with her.

Doesn't matter who, either. Thieves, pirates, Alliance, even Reavers if he had to. He'd fight any of 'em to keep her safe. He's not going soft for her. She's special, that's all. Living as a thief, he knows the importance of protecting special things.