There's an acoustics research facility in Minnesota, Orfield Laboratories, which is famous for having the quietest room on Earth. It's used for testing products to see how much noise they make, and there are no echoes because the walls and floor and ceiling absorb all sound. In the absence of other sounds, occupants become overwhelmingly aware of the sounds their own body is making, and don't hear the soft echoes they subconsciously use to orient themselves as they move around. Most people can't stay in there longer than 20 minutes; the record is only 45 minutes. If there was ever situation that called for using {tamchu'} (or even {tamchu'qu'}), that's it.