What would you do? Short Sale!

[Colbert Saint-Laurent]

I am in the process of buying my first Short sale in Fort Greene , Brooklyn. We are in the final stages but that came to a stop because the we person we are purchasing the property from does not have the deed in their name so obviously its a "A to B, B to C". which is fine we are still getting the property for 600k and the comps on the block are selling for the minimum of 1.2! Our only concern is if we write a check to them and they don't pay off the bank and run off then I loose all my $. What would you do?!