You just need a better imagination.
Most likely, they'll cut away before Tsukune makes the "big decision" to show the other girls, and then they'll show up, and Mizore will be all like "Sorry, I was horny and ronery; he rejected me, though". But that's where you realize that this is just the calculated plot of Mizore and Tsukune. They bumped some erotic and icy uglies and then thought of how they would cover their asses and make amends with the others.
In the RV I've been reading, Tsukune's had lots of sex.