I think that the guy was panting at the end because he Has crush on mc, but he is weak to her (?)(trough he wasn't blushing, but i rather think that their feeling is mutual xDD)
((Ps. I know that the boy is prob into someone else, since he mentioned something about a girl who taught him pen spinning (i dunno the right name for it) ))
Sry for my english and my messy and mixed writing, since i couldn't interpret it the way i wanted, so u may not get what i mean :/