You met Maki's twin before the Kyoto Sister-School Goodwill Event. Mai bullies you to get under Maki's skin, it's working.
Mai addressed you with a mocking grin on his face as he held a gun up to your chin, asking, "What's your name, little mouse?" He leaned in even closer, studying your features.
At that instant, Maki intervenes by knocking his gun away, sounding genuinely disappointed.
"You never change, Mai," he chided, sounding disappointed.