Well... That was unexpected! I thought we were going to have another tomboy flat waifu (whoever doubts they will all end up joining the harem is just coping), but instead we got an ultimate attack, capable of destroying even the supreme armor (the corset that somehow kept all of that in). Then again, said armor probably was already under a lot of tension and stress, so it could be the case that MC just gave it the finishing touch... BUT, even after taking the hit head on, she got no harm done to her, so I'm betting on the durability theory.