I am having trouble finding any treatment of this topic on the internet.
A couple who has been having sex suddenly discovers that a blood flow has begun. Are they liable for kareth? Leviticus 15 seems to speak about kareth for merely "exposing the source of her blood", but perhaps the same principle applies as when an axe accidentally flies off the handle when chopping in the forest?
Furthermore, what if this occurred not during the expected days, but eg a week before? So the woman was not checking her blood flow before menstruation. So she is now considered a zavah, correct? And she must count to herself 7 clean days after the blood flow stops?
I would like to understand, with sources, what our sages teach in the case of an sex during an unexpected or early period.
Please bring actual sources.