Dimensional transporter

Medallions were devices that allowed people from Pete's World to teleport to the same place in other universes when the Void was open. It also allowed the TARDIS to travel to Pete's World.

The S4 version of the medallions allowed Inter- and Intra-Universal jumps. Inter-universal jumping, as before, only allowed one to jump to the same place in an other universe. Intra-universal jumping, a new feature, allowed one to teleport to an other location within the currant universe. Exactly how the destination is input is unknown but the disk might be able to scan your brain to find out the desired destination, or they might just teleport to the nearest other disk.