OK, in my film there is a scene where a man named Atticus has a gun pointed to his rivals head. It looks a lot like the scene with Tyler and Raymond K. Essel from Fight Club. You can see a close-up of the victim-rival's head and in the background, pointing the gun to the back of his head is Atticus.

Then he fires the gun and blood shoots out of the victim's mouth and he collapses on the floor.

Sounds simple enough but how can I manage this. I'd usually do something with compressed air if the blood were coming out the back of his head, partly hidden by the camera, but how can I make it so that this bloody ejects out of his mouth?

___________________________________
You can't keep 'em out, they're already in!