Peter stops himself short of making some sort of inappropriate joke. Honestly it was probably just going to be something lame like 'oh baby' which is. Like. Barely a joke and barely inappropriate, but he's a weenie and doesn't want her to think he's some kinda weirdo and just you know what he's going to just stand aside and let her remove that casing. He'll make himself useful by keeping all the screws she removes together or something.

"They coming out okay? I ran into some stripped screws earlier on another piece of equipment that were just a nightmare to unscrew."