Sasha says: "The remote is synchronized with the base unit, so if I move it to fiddle with it, they won't be able to use the remote at all." I suppose anyone is free to believe that Kusari lies for some unknown reason.
Riff says: "Oh wait, I need that!" He doesn't explicitly say what he needs the DFA for, but on the agreed-on date he
returns to the same spot and sets up the DFA.
They always call it a "remote", which suggests that some kind of remote control is involved. All things considered, it has until now been very easy to get the impression that the remote remotely controls the DFA to open a portal to the universe where the remote is.
If Montgomery has now made a pocket-sized, self-contained, non-random DFA then that's nifty, but in that case it's misleading to call that thing a "return remote".