https://www.youtube.com/watch?v=tkW7SOKdcY8 

Dear HBC People,

I have been on several club rides when a riders shift cable breaks, and they have to struggle home in the smallest cog ( highest gear). This whole video is worth watching, however at about 6 minutes are instructions on using a wire tie to ajust the derailleur so your bicycle is not in the highest gear, making the ride home easier. Since seeing this video I have added a few wire ties to my saddle bag.  Use the above link to watch the video.

Happy Biking,
Bruce