Does timing chain give warning signs?

Do you get any kind of warning signs before the timing chain goes?

How does a bad timing belt sound?

What happens exactly when the timing chain goes and how many dollars are you looking at spending if it goes when the engine is running, I know it costs about $1100 to replace the belt but what damage will it do to the engine of a 1994 E420.

It's hard to believe and dissappointing that there is no permanent fix for this problem yet.

Thanks for your help.