That isn’t true. The headsets used in airplanes have microphone elements on both sides of the mike boom. The ambient sound reaches both sides of the microphone at the same time; and, is electronically subtracted from each other. The voice of the headset wearer strikes mostly the side close to his face, so is strongly unbalanced with respect to the other side. The voice is not subtracted out.
10-4. The next time you see a cop on the street go up to him and ask him if he has the same comm system that they use in airplanes.
Police radios are what they are. Other than that, I have no idea what you’re talking about.