She's passionate about medicine! And not acting completely terrified! "Which is very laudable! Just don't burn yourself out."

"Well, you shouldn't burn yourself out either."

"I'll do my best not to."

Biana is trying to figure out how to direct this towards getting drunk with her--

--when they stumble across Quina vivisecting a rat. 

...

???

He did not expect his students torturing small animals to be a problem he would encounter.

"Put the rat down."

"I'm sorry, is my technique wrong? I haven't done a vivisection before."

??????

... he is dealing with a literally medieval society. But even medieval societies have a concept of animal cruelty.

... he's going to have to keep chasing down those weird ethical holes, isn't he?

He is not going to yell at his student. Yet. Not while the rat is still twitching. "If you're going to kill it, kill it quickly and kindly."

She breaks its neck, then says, "my mother said that vivisection gives you a better understanding of the functions of the body in vivo."

... that's... probably factually correct, but very much not ethically. "When it's time to learn anatomy, you will be doing supervised disections. Until such time, you will not be torturing rats in your spare time!"

She makes a mental note to tell the students she dislikes most about the usefulness of vivisections. 

"My apologies, sir. I didn't know that was the rules and will follow it in the future."

"I'm very glad you plan to." He pinches the bridge of his nose.  He's going to have to work out all the other places his and the students' assumptions don't align, and hope there aren't any more victims than that poor rat.

Quina quietly cleans up the rat and leaves.

"That's terrible!" Biana says, hoping that Bun won't ask her what's so terrible about it. 

Biana has actually lived in this culture, and should hopefully have some instincts about it.  It's good that at least she thinks its bad? "-- is this something I'm going to have to tell everyone not to do?"

... this would be a bad object lesson on informed consent, on account of the rat not being informed being the least of the problems.

"Yeah, I think so," Biana says, continuing to hope that Bun is not going to ask her more questions. 

"That's going to be a fun dinner announcement."

"Are you taking a break?" Biana asks, avoiding subtlety. 

"I don't have anything I need to do in particular.  Why do you ask?"

"Well, I don't have anything in particular I'm doing either, so..."

"You don't have to follow me around. You can go relax."

"I think spending time with you is very relaxing."

... he's just going to presume innocent intentions here. "That's good to hear."

"I do have some fine wine from the River Kingdoms up in my room..."

...nope, no innocent intentions here.  "That's a kind offer, but no thank you. "