Really funny to me that graceful, dignified Rin is just BOOKING it

Sensei got that belly scar, courtesy of Saori

Why Hanako is still contemplating, she would have already be in her swimsuit during this...or worse.

Hanako is contemplating
Ako doesn't know if she runs or stays
Kayoko is tired and doesn't care
Rin is getting the hell out of there
Ayumu already left
Ayame is too embarrassed to look
Yuuka is trying to warn Sensei
Himari tripped because of Rin
And so did Momoka

... Yup, sounds canon to me