The film co tried to save money and cut major corners. If you read the emails between the armorer and other people involved in the movie, you would know the armorer was begging for people to attend a safety class and wanted to spend more time on the weapons rather than the props she was asked to take care of and was denied.
And people who are familiar with guns know you NEVER point a gun at anyone and ALWAYS assume a gun is loaded.
How nice for you to give a pass to a pompous, arrogant, remorseless man who shot a young mother, blamed her for her own death and walked away from her while she lay dying in a puddle of blood.