Responses
Yeah, the whole scene is kind of messy, but it makes sense since Azusa had the King card (from Atsumu) and later Karino is shown to be the King, I always thought he:
1) Pushed Asuza from the stairs to incapacitate him
2) Go to an empty room, rape him and steal his card.
3) He left him there so he could Finish the game and once it was all over, he went back to Asuza and mock him.
I just started reading this is karino the one who raped the uke at the beginning or did he just show up after someone else had