Question: Is it really possible to stop blood flowing from the brain with a pin stuck in the neck? Also, why does the blood not flow again after Jet Li has removed the pin?
Answer: The acupuncture point known as "Point 15" is in a delicate area of the spinal column, a little below the second cervical vertebra. It's a definite knock-out target in fighting, and it can even be a lethal target. But Jet Li's explanation that it somehow prevents blood from flowing away from the brain is pure nonsense.
Answer: 1). Yes it is possible. 2) If you listened while Li told the dying man what was happening, he said that when he pulled the pin out, the blood WOULD flow again, except: because of the empty blood vessels, there would be a vacuum effect that would suck too much blood too fast... therefore the guy dies.