How to run away and still have a chance!

If a army of Zergs,Protosses,and Terrans come out of nowhere and destroyes almost everything,make the buildings fly in the sky to land.(It won`t work on Pros because is they are Zergs,he will bring in a bunch of hidrilasks and muskilats,he will kill all of your flying building.The Terrans will bring marines and wraiths to destroy them too.The Protosses?Well,if they are around, they would kick your @sses because they hav a lot of flying units,also strong!They have dragoons and other stuff.WARNING=U MUST HAVE A C.C TO DO THIS!!!!(Command Center).You have to have it because the SCVs can build new things!You can produce them at the C.C. If you don`t have it, your a GONER!