[There is NO way she'd understand a real explanation. His smile is a little exasperated.]

I promise it's harmless to you, aside from the momentary annoyance. But... alright. Just this time. [He knows he needs to pick his battles, so he puts the chemical to the side and prepares the gauze and wrapping.]

Would you be willing to come back here to let me check on it?

[It's a good excuse to keep an eye on her... if he can get her to agree.]