Ryuutaro would never tired of seeing Hayato's behavior change like this, least of all when he was the reason. And if it was added by something like Yamamoto's startled look, which naturally did not go unnoticed, it made it even better. Ryuutaro had been developing some kind of possessiveness since they came to this world, similar of how Hayato had been when people recognized him in his world, which would probably vanish after a while, but hadn't yet.

"Not too long, don't worry."
Ryuutaro closed his fan. "Are you feeling better?"
If Yamamoto had known Ryuutaro, he'd notice that Hayato wasn't the only one who's behavior completely changed when they were together. Maybe it was much less noticeable with Ryuutaro, but the changes clearly were there. Being with his boyfriend filled those empty masks he wore with honesty.