Star Date, do you mean the scene where Alto carries Sheryl into his locker?? That was episode 5?? They just met for the third time? and LT hasn't really started yet
And that "pivotal moment" in 22, unfortunely Sheryl's sickness does contribute a bit there...Of course, "sickness plot" is nothing new in other romance series, male lead sometimes pick the one who has sickness and sometimes he realizes he loves the other one. But in my opinion, the LT hasn't handled well because in 22, we don't know how big the sickness from Sheryl has influenced Alto's judgement (and we never know that even when the series finishes), then we see Alto's speech in 23 regarding Ranka, in ep 24 Sheryl says stop playing the lover game...Alto was trying to say something, but we never know what he was trying to say, and in ep 25, Alto says you two are both my wing....
So I think audiences still have not enough resource to analyze Alto's deep feeling towards Ranka/Sheryl...he just thinks of them not enough XD