Well that was a reaction. Sasuke's brow raises just slightly as he takes it in, making a mental note to not use the word around him again. He's curious as to why it strikes such a chord in the other man, but he's never been one to pry about anything.

So instead he goes to pick up the broom from the floor, offering it back to Shiro.

"Don't apologize. If you're falling asleep on your feet, it likely means you're working too hard. Taking care of your well being is just as important for being efficient in your duties as dedication is."