A typical medical case's progress through the clinic looks like this.

AnimalProgressFixture
new case	Betsy	Rankin		Rankin brings in a cow
diagnosis	severe mastitis
order	intensive care
charge	100			diagnosis costs $100
check	balance	100
day passes
check	balance	140		intensive care is $40/day
day passes
check	balance	180
diagnosis	mild mastitis			now finish treatment
order	normal board
day passes
check	balance	196		boarding $16/day
day passes
check	balance	212
payment	212
check	balance	0
order	discharge

But sometimes animals die.

AnimalProgressFixture
new case	Susie	Busboom
diagnosis	severe mastitis
order	intensive care
charge	100			diagnosis costs $100
check	balance	100
day passes				intensive care costs $40
dead
order	pathology			pathology costs $80
check	balance	220		shockingly, you have to pay even if the patient dies.