Depending on the type of "Colt" revolver (still unknown) then the person handing him the firearm (the AD in this case) either opens the cylinder, which takes less than 1 second, or opens the side gate and rotates the cylinder (takes 2-3 seconds). At that point we can split two ways - if the weapon is "cold" then there should be no rounds viewable so, as there would have been Live round viewable, that would break the chain or - alternatively - upon opening the cylinder if there was supposed to be a blank fitted, the AD removes it (another 1-2 seconds) and shows Baldwin and either person could say "hang on, that's not a blank" and again the chain is broken.
Finally, if it was a very old "cap and ball" revolver i.e musket type, then you can look into the front of the cylinders to see if a "ball" is viewable (the bit which actually shoots out the end of the barrel in a Cap and Ball revolver) and if a ball is seen then the chain is broken once more.
All those actions should take around 10 seconds start to finish and thats how he could have been shown. If however the AD isn't able to do this then he shouldn't have been the person to be handing over firearms (production hiring problem) and instead the Armourer should have done this instead.