Initially i wanna do a video editing to “enhancing the proof” but then i realized that my video editing skills is as good as my dancing and singing skill which is nonexistence. So here is my observation breakdown.
00:00 — 00:02 Moa looks like she holding her face trying not to laugh.
00:03 Moa cant hold it any longer and smiled while dancing.
00:04 Su seems like smiling for a sec because something she did behind those kitsune mask and back into the character at 00:05.
Another reason to love those girls i guess. I also notice that Yui also saw the funny face but she doing well holding in.