He was cut in the carotid artery. Thats the only artery that leads to the brain. Remember, arteries carry oxygenated blood, which means his brain was probably loosing oxygen. I think he's going to be alright but he could've gone brain dead if they hadn't acted fast.{Most info came from Sec, but I understand it lol. I forgot everything about arteries from health last year D:}
WARNING:BLOOD IS IN THIS VIDEO. DO NOT WATCH IF YOU HAVE A WEAK STOMACH WHEN SEEING BLOOD!
Note: They show two replays from two diff angles.