"SecUnit it is then, darling" it's not like he could use Rin even if he wanted to, 'many prefer to' isn't exactly permission, after all. Well he could but it would take more effort than it's worth just to, what, use a name it doesn't even want?

"I'm simply delighted to be the first, darling, and I'll be sure to call you darling in person too when I next run into you"