Mikan seems unfazed.
Normally you'd expect her to be at least a little traumatized by that sort of thing, but given her expressions of "What even is going on? Why am I here? Woah that was kinda cool" I think it might've happened so fast that she felt like she was just on a movie set or something. On one hand, arguably lazy storytelling. On the other, I don't think I mind too much, it's just a simple formulaic feel good story where we can watch the flirting, cheezy badassery, and gap-moe of a high school urban fantasy power couple.
Also gotta say girl, I know you really want your knight in shining armor to confess to you, but you've also professed that he's not only the strongest guy, but also the cutest guy ever. He's also dense and a bit of a shrinking violet when it comes to friendly interactions so go and claim get him!