"Misfire" - is pulling the trigger, expecting the gun to fire, and NOTHING happens. Could be a problem with the weapon, or the ammo.
"Accidental fire" - is when someone fires a weapon when not intended to. Operator error. Like walking around with your finger on the trigger, and.. ooops.
The gun did not "misfire", and really wasn't "accidently" fired. It was fired intentionally, without being checked to see if it was safe.
Single action revolvers don't accidently fire themselves.
The hammer is manually cocked and then the trigger is pulled.
And why the heck was it pointed at a person?
And before someone says that they were filming him shooting at camera... my $500.00 Nikon D3300 has a remote option. You know that those high powered movie cameras have remote options. If that pistol was fired at the camera with a person or persons standing right there, yet another HUGE mistake made by either the person calling the shots.. or the person firing the weapon.. or both.
Many people have many things to answer for.
imo