At one point "The Man" kills one of the masked men and takes his gun. Later he reloads the gun but he never took the mag from the dead body.
While tied to a chair in an abandoned warehouse, the murder suspect has a large nail driven through his hand. Later, however, this serious injury doesn't bother him when he uses a crowbar to pry open a heavy steel door, effectively fires several weapons, and works himself through many confined areas while trying to escape.
At one point, Ron Eldar mentions that he has never fired a gun in his life. Later, however, he fires both a pistol and an automatic rifle with the skill of an experienced soldier or police officer.