[... Yeah. Seeing as how that point is definitely the wrong way...
She starts walking the opposite direction, leaving him to look dumb in his pose.]

I'm Koizumi Mahiru, by the way.
And it's rude to make a girl introduce herself before you do.

[Which means he should have given her his name long before now!!]

I'm going to guess you're new to this place, right? So you'll be turning into a monster yourself, eventually.