  Do you mean the Ring or the Arches? It's clear the Arches are not a direct entry way into T'A'R Proper, and certainly take into account a mix of T'A'R properties with Mirror World input data, and create something of their own, which turns into something akin to a dream bubble of a Mirror World inhabitant that matches the individual walking through the Arches.  Not that this particularly matters as far as your single use argument, but thought it useful to clear up. The ter'angreal ("Acceptatron?") in the White Tower is T'A'R based. (RJ hung a flashing neon sign on that one with the interaction with Egwene's ring)  