What about the memory crystals

"Man theory classes after lunch sucks." Rio said, as he washed his face, after being caught sleeping in the class. 

"Can you stop complaining and be faster? We're late." Takashi said, as he was kicked out too. 

"Come on. What's the rush? Let's go get a coffee first. Or you're gonna fall asleep again." Rio said, as he started moving towards the vending machine, which are placed on every floor of the academy. 

"No. I'm leaving. You're wasting our time." Takashi said in a hurry, while trying to catch up to Rio. "And I didn't fall asleep. It was only because I was trying to wake you up that I'm kicked out too."

"Did I ask you to wake me up?" Rio said and looked at him with a serious expression "Not my problem if you got a habit of butting your nose in others business."

Takashi noticed the difference in tone, but he still defended "Classes are a sacred place. I can't just let you disrespect them like that."