"... [it is] a Shatner Acting Technique™ I've dubbed The Bill Shatner BeerFace™, whereby Shatner acts as he has either never tasted alcohol before or that it is of some unbelievable proof and potency as to cause him to wince, then grimace, then look at the glass to make sure it's the same beverage he was sure he poured into the glass. Works with beer, wine, liquor, Romulan Ale, Saurian Brandy and even plain old water. He basically does it when drinking any beverage..."
Captain Kirk was taking a bathroom break, the prop stylist removed the firing pins from the pistols, just to be on the safe side.
Good night, sweet $#*!