I am going to guess that the writers were thinking about the fact that a revolver doesn't have a safety. The best way to carry a revolver is to have the hammer sitting on an empty chamber giving up one shot.
Cowboy old western pistol didn't have a safety and some were single action.
Millitary and Police revolvers all have safety catches as the hammer strikes a firing pin, which can be locked in place.
Revolvers have one huge advantage over automatic pistols.... they don't jam or have stoppages.
The only pistols I've shot with, back in the 1980's, were the Browning 9mm., Star (a Spanish Berreta copy) and the .357" Magnum. I prefered the Magnum as it hit exactly where I was aiming it.
Other guns include 30mm. Rarden cannon, Browning M.1919-A2 and Lee Enfield SMLE Mark.V.