....... the knife he bought in the table (nevermind how it got through security
). ......
There was no such thing as "Security" at the time which the story takes place. No such things as metal detectors. Then, the only way to search was a full body pat-down and you know what kind of reaction there is to that, even today with the threat of shoe bombs and hi-jacking and .....! As an example, I have in my collection a .32 revolver that I was given by my father, an attorney. He got it from a client during a murder case in 1957. He normally did not do criminal law but was the court appointed lawyer in this case. They were in court and the prosecution was petitioning for a search warrant for the client's home. Dad quietly asked her if there was any problem with that and her response absolutely floored him. She said "I'm not worried, I have the gun here in my purse. They can search my place all they want and they'll never find it!". Dad took her out in the hallway, took the loaded gun and extra ammo and put it in his brief case and they went back in the courtroom..... still with the loaded gun and ammo. Nope. No security back then.
She was later acquitted on a ruling of self defense, but dad kept the revolver and years later he gave it to me. It has been used many times in shows since then, but with a few modifications. I have a second
barrel with a reduced bore that will not allow a round to
pass through, but will allow a flame front to propagate out the front of the
barrel rather than the top or sides like many blank or wad cutting pistols. This can be a requirement in film, video and some low light
stage applications. The second modification is a second cylinder with a shortened cartridge chamber. It has a full diameter bore only deep enough to allow a blank cartridge/shell case to be inserted. Any cartridge with a bullet can not be inserted far enough to allow the cylinder to be closed. Of course in any production where the weapon is only a visual, the firing pin is removed. I do my own blank loading so I can control the material and amount of wadding as well as the strength/amount of the powder load.
Of course this is exercise in debate and has nothing to do with the OP's Q or the show itself. HOW the knife got there is immaterial to the to the show or the question. The type of knife is also immaterial and is up to the director and/or designer. The real issue and solution is what others have already said. Blunt and dull the implement. Conceal a "soft" area in the table, florist's foam and clay are two of the best but blue or pink foam will work, even white bead foam will work. The "
Point" of the issue is the "
Point" of a knife, even a very sharp one is actually rather difficult to "stab" hard enough into a hardwood table to make it stick and stay, reliably, every time. Hope this helps.