I'd bet my life Kei has a Master's Degree in flirting. I mean, how could you ask for help in unbuttoning your shirt and later on reveal that you're actually ambidextrous???
I feel REALLY HARD for the MC. You admire people not because you want to date then but because they've unconsciously helped you during the times when nobody extends a helping hand just by merely existing.
The man's keeping his word so you can be all tsundere all you want.