We have an assurance that there is a promise with her.
Yeah, but I honestly hope that Hana and Kaede don't get in the way then. Usually they would interfere and if they do that too often, even someone like Aya might actually snap. Ideally I want Aya and Sou to have a private moment where they are alone and can actually talk. But as things stand that won't be easy to achieve at school. Currently there are several troublemakers that need to be dealt with first:
Yuri is probably incapacitated, they could just carry her back to her seat.
Ruri is more complicated. Let's hope the scent bomb hit her so unprepared that it knocks her out.
Aya as the team leader could order Hana and Kaede to take Ruri away before she regains her senses. The destination would be either outside (maybe the school roof), the infirmary (also a long way) or back to Class D (would result in explaining stuff to Ruri's team members)... but essentially the others would be gone and Aya gets Sou for herself. At least a little.
Well, they wouldn't really be alone, but Aya could find a way to arange it. Perhaps by taking him to a restroom before the final classes start. If he doesn't want to, she could fake that she herself needs to go and ask him to come with her since she cannot leave his side as his guard... a gentleman wouldn't dare to object in that case. even someone as dense as Sou. Unless he has a certain fetish. Let's hope that's not the case. Wouldn't be very romantic, but Aya has little options at school.
Or she pulls Sou into the locker after the others are gone, but I don't think that's gonna fly with her. Aya is not stupid or suicidal enough to pull such a stunt.If nothing works, she could at least asks him for a video call with her later that evening. That way she only has to get away from Hana, but that should be possible.