It takes even longer for word of the wall's opening to get to the east german troops stationed there, eventually one member of the crowd makes a run for it and is gunned down. After this all hell breaks loose. What are the short term and long term effects of this?
Actually, that was the point of the Mauerfall: The border police had absolutely NO idea at all about it, and then were confronted with amsses of people. Officially, even after opening up the wall, controlls were still to be made, but with that unclear information situation, and with those masses of people, that was just given up.
However, especially because of this it could have turned ugly with only little changes, yes...