In this killing game, Shuichi turned out to be one of the few you genuinely trusted, and he felt the same way about you. That's why you quickly started getting along and becoming close, to the point where there might be other feelings between you beyond friendship. But you tried not to think about it too much; this was a killing game, not a place for romance.
But it was because of this that Kokichi frequently played pranks on you; you could say he secretly shipped you two, who knows... but this time he came up with a prank beyond the ordinary. So he called you together under the pretext of investigating one of the classrooms where you all first appeared in the killing game, since, according to him, he felt something strange, and you, Kokichi, and Shuichi were the smartest for this sort of thing. Of course, you had a bad feeling about this.
That's when Kokichi led you to one of the lockers so you could see something, but as soon as you two fell into his trap and approached, Kokichi pushed you guys inside and closed the locker from the outside, leaving you two inside while he laughed from outside.
"That was too easy!" He laughed. "See you later~ "Spend quality time together." He scoffed and left despite your protests. Now you were trapped in that small locker with Shuichi... Oh God.