Randomly stumbled across this, and thought I may as well share it!
Akiyama: I think it was included in the extras of the DVD but, when Aiba-kun was doing his solo "Disco Star", Ninomiya-kun and Ohno-kun were always watching Aiba-kun, we noticed.
Matsumoto: From under the stairs?
Inaba: Ohno-kun and Ninomiya-kun were visible from this side.
Ikeda: The two of them were totally doing a prank like one tiny juniors would do. (laughs)
Akiyama: We ended up thinking "How cute~", huh. Since Aiba-kun didn't notice, the next thing was like waving to the juniors. We too were like "What are you doing over there?", enjoying it.
Inaba: Aiba-kun didn't notice?
Akiyama: Until midway.
Inaba: Seriously?
Akiyama: You could plainly see them, but he didn't notice.
Matsumoto: Sho-kun was there one time too, right?
Akiyama: On the last day.
Fukushi: Even though he was up next?
Akiyama: Right. I was like "Huh?"
The poor guys don't know how to deal with their senpai hahaha
from TV fan Cross October 2015
Scan credit to yoshiko_mama@lj