One scene that is kinda odd.

I think there's a bit of suspension of disbelief that he didn't recognise her voice, maybe. But it's not like he knew her well. She was one of loads of people he knew just as an acquaintance. And her mask could have been enough to prevent him from recognising her face if he's one of the people who recognise faces centrally (people who are also thrown によって people wearing sunglasses).