If Renji had known it would turn out like this he never would have locked Kira and Hisagi in that supply closet—at least not alone—because ever since the two had become an item, which sometimes got Renji wondering what the hell happened inside that supply closet, he's had to put up with the craziest shit.
If he had known he would have to sit there and listen to Kira and Hinamori giggle over whatever Kira and Hisagi did the day before on a daily basis, he never would have asked Kira go get the jug of sake in the supply closet.
If he had known that he would have to fight tooth and nail to keep a drunk Kira away from an equally drunk Hisagi—NOT when they had drills they would need all their strength and energy for the next morning, damn it!—he wouldn't have asked his senpai to go help Kira find it.
And if he had known how horrible the sight of the entire female populace mourning the loss of the chance to be with the handsome 6th rounder or the charming blond freshman (though in Kira's case, it was mostly the male populace mourning) would be, he would never have let Hinamori talk him into slamming the door and locking it behind his two friends' backs.
Hell, if he had known he would spend his entire freshman year putting up with a paranoid and insecure yet happily in-love Kira, a jealous and overprotective Hisagi with his head in the clouds, a bubbly, giddy and constantly conspiring Hinamori, and an explicitly detailed account of the couple's sex life he would have gotten the damned sake from the damned supply closet himself.
Frickin', non-existent foresight.
"What are you talking about, Abarai-kun?" Hinamori scolded him when he told her as much. "They're so cute and happy together! You did the right thing!"
He rolled his eyes and grunted noncommittally. He should have known the person who helped Kira dress up for dates wouldn't agree with him.
He heard familiar laughter come from ahead of him and he looked up to see Hisagi sweep Kira off his feet and carry him off to God knows where to do God knows what.
Hinamori giggled and Renji changed his mind.
If Renji had known it would turn out like this he guessed he still would have locked the two in that supply closet, after all.
He just wouldn't have let them out again.