In reply to sjc:
Show them, preferably in advance, how to set up a backrope. (You are climbing on double ropes, right?)
Reverse the traverse and ab off? But wait, "inescapable" you said? Really inescapable no matter how much gear it might cost you? It's still more sociable to await rescue together than at opposite ends of the traverse.
You made sure they know how to prusik, right? How poorly protected is this traverse? They can fall off, prusik up to the gear, repeat as required ... unlikely to be either fast or much fun for them, granted.
Rethink your choice of route or partner next time?