Allison gives Astrid the airport code "BER". The IATA code "BER" refers to Berlin Brandenburg Airport which, due to extensive delays, won't be opened until 2019 or later. There would be no point in planning an attack there.
At Berlin Hauptbahnhof, there is no underground line going to Potsdam. The S7 at the top platform goes there. Only the U55 with three stations in total on the line leaves from Hauptbahnhof. It is in a separate compound next to the Hauptbahnhof building though. The lower platform is for local and long distance trains leaving north-south. An S-Bahn line is currently build underground, but not yet finished.
The goof item below may give away important plot points.
After Allison shoots her handler with his gun, she does not wipe her fingerprints off the weapon before laying it down next to the victim. For an experienced CIA agent hoping to frame someone, that is a big oversight.