I have to echo the sentiments and comments of the other brokers who've responded to your question.
There are too many variables and/or "unknowns" here, e.g., contingencies, timing, how long the other party was in the pipeline, etc.
Short sales are very unpredictable and it is the reason why many buyers prefer to avoid them. So many buyers think that a short-sale will result in a real savings. In fact, while a party is making an offer on a short-sale or potential short-sale property, they could be passing up an opportunity to purchase a house that they really could have.
Buying a short-sale property is walking a minefield. One has to be very careful and nimble.
You might be better off dealing directly with a seller who is eager and motivated but not necessarily under water. Or, consider looking at REO (Real Estate Owned) properties where the bank is motivated to sell and the title will be free and clear.