I am one of the few people on the board who has seen someone bleed to death from a neck wound**. This is what I know:
If she cut an artery, there would be massive arterial spurt. Holding her hand over the wound would be like putting your hand over a tub running at nearly full blast. There would be blood everywhere, not just running down her hands in an appropriately movie-like way. When the young man was dying, I marveled at how much his body was shaking as the blood was ejected, at full force, from from his body. That's what attracted me there in the first place: I thought he was having a seizure.
It's more likely she cut the jugular vein, which is both outside of the carotid artery and more likely to ooze, rather than spurt. That would give her time to bleed out attractively. For more on how the neck bit works, see http://bp2.blogger.com/_Ctfv1n5l1ok/Rvm ... _veins.png
**He was a worker at a CVS. There was a robbery and his manager chased the suspect, so the young man followed as well. The thief stabbed the boss in the gut and cut the kid's throat. I was driving a car back to my then-workplace and found the manager and the kid. He died in front of me. It was an awful waste. There is never, ever, a reason to chase a thief.