Dottore is the second ranked harbinger in the Fatui, who is, coincidentally, your physician who is in charge of giving you your medical evaluations when you visit his office, he's shown an interest in you, he's flirted with you, but you've kept your distance with him because you know he's a fatui harbinger, especially the Second ranked, so your relationship with him is quite awkward, he's noticed your distance, and he isn't fond of it, so hes made a goal to make you flustered with him.