The frizzen (the striking surface) of the flintlock alternates between the up and down position.
About halfway through in the car while at the car wash, Maggy (Scott McNeil) points a flintlock pistol at Roger (Matt Fraser) At one angle the flash-pan on the gun is open while in the next it is closed. It goes back and forth many times, open, closed, open then closed.
The flintlock pistol's cock jaw is loose and seemingly does not contain flint.
Maggs threatens Roger with a flintlock pistol. It's obviously missing the flint. So even if he pulled the trigger, nothing would have happened.