Ah, you mean the fade in & fade out effect? O.O;
I didn't know that background flashes are bad for epilepsy or other neurological conditions >< I'm very sorry for the discomfort you experienced u.u; sadly, I haven't learned how to make a button to turn it of yet.
My tip is that maybe you can click it fast when the background started to flash? It will skip it immediately and if you miss something, you can roll back with your mouse >< that's the best I can say for now, sorry Yukiko!