If it was a handgun, highly unlikely even a real bullet would like not go through and strike another... not while being fatal to either victim. There is always the remote possibility that a projectile grazed the director on her neck (or other major blood vessel) then struck another.
And a handgun is not going to produce shrapnel, unless it strikes something crazy unlucky that creates fragments that even more rarely causes fatal injury.
Going to be interesting to see where this ends up. Goofing around with a prop gun is plausible. As mentioned, if close enough the percussion from the blank can be fatal if held to the head.
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