I thought that the fire from a flintlock pan went primarily out the side as well, until I helped support the heavy barrel of a longrifle for a young shooter shooting his first shot. I supported the barrel well forward of the lock area. I now have a life long reminder of the event in the form of some tattooed freckle in my forearm. I was shocked that so much fire was able to escape between the frizzen and the pan, and how far forward it traveled.
Hungry Horse