The glyphs from this episode spell out: FATHER
The Observer is seen walking outside the cafe, when Alfred Hoffman is talking to the patrons.
The chafing-dish warmers used to attack the tolerance conference are blue, and contained in metal canisters. This mirrors the color of the gas crystals and containers of the infamous Zyklon B gas used in the gas chambers.
This episode includes an appearance of the running joke in which Walter can't quite recall Astrid's name correctly. Here he calls her "Ostrich".
In the opening scene the wedding is most likely a Jewish wedding and in the background the Ketubah can be seen. The ketubah is a Jewish marriage contract. It is considered an integral part of a traditional Jewish marriage, and outlines the rights and responsibilities of the groom, in relation to the bride.