Continuity mistake: Blanc says he has no idea how Fran got hold of the toxicology report; in that shot, wide angle, Marta's hair cover her right side of the collar of her coat, like in most of the scene. But in the close-up that follows, when she blurts out of the reason, her hair is on the inside of it. (01:54:10)
Continuity mistake: During the denouement Marta asks "So why did she send it to me?", and Benoit Blanc replies with his right hand in mid-air - but it's in his pocket at the beginning of the next shot. (01:54:30)
Continuity mistake: When Ransom asks "Fran's alive?" to Blanc, Chris Evans has his hand raised, thumb before his lips. But the hand is lowered in the shots before and after. Similar situation when the word "Jail" is used a few seconds later. Hand visible in close-up, not matching the wider angles. (01:58:10)
Continuity mistake: The quantity of barf on the killer's face varies between shots - in particular they have a big reddish bit on a cheek that disappears in the dramatic slo-mo side view when they push Marta down, weapon in hand. (02:00:00)
Continuity mistake: When the detective (Benoit) asks Marta to be her "Watson", the wind is blowing hard enough to move their hair. In the reverse shot, it is calm.
Continuity mistake: As the camera is panned wide with an aerial view of the estate there are no leaves on any of the trees. But as Marta steps out of her car, the trees are full of very colorful leaves.
Continuity mistake: When Ana runs out of the gates in the back yard they're left open, but when Ransom returns at 3 am they're closed. And even though it hasn't rained for a week it is still muddy.
Answer: To add slightly to the other answer, evidently some of the blood in the scene had to be digitally removed for the film to secure a PG-13 rating, which explains why we don't see any actual spray/gush. But we are to assume that a drop managed to splash onto her shoe when he slit his throat.
TedStixon