Eva wants to relieve some of her nervousness by having a party in the Chancellery's reception hall, which is located directly above the Vorbunker. She tries to cheer people up and motivates them to dance with each other.
Some time later, as the party is underway, Fegelein watches Eva from a distance, then decides to interrupt as she dances with Hewel. He urges Eva to leave Berlin, or to go with him, but Eva simply turns away. Fegelein then gets her attention back and tells her she will die. Eva looks upset and turns away again, to rejoin the party. Later on, as people are drinking and dancing, a shell fell near the hall, skipping the vinyl record. Eva then asked if anyone could make music, a man replied and went to the piano to play. He asked Eva if she has any requests, to which she replied Swing music. As the music starts, she climbs up onto a table and starts dancing.
Traudl, seeing the oblivious Eva, felt sick in her guts. Gerda approaches her to offer some consolation, and Traudl told her that she felt like in a trance or dream; she tried to wake from it but can't. Shortly another shell dropped next to the hall, shattering the windows. Amidst the debris and dust everyone scurries back to the underground network of tunnels.
In the Parodies
In the parodies, the scene is used to depict some sort of party - usually with the music changed into an EDM or the like. Some parodies use the part with Fegelein and Eva when the former informs of a new antic, or drug use. But all kinds of scenarios have been used.
Eva's face as she dance on the tabletop looks like a duckface, as seen in this video loop.
The part where a shell hits the hall is usually depicted as a result of an antic, explosions, Hitler ranting, or a runaway kart smashing into the hall (Super Hitler Kart).
Trivia
Hitler does not appear in this scene.
Hewel has a line in English: "May I have the pleasure, Fräulein Braun?"
A Högl lookalike is seen in the background, although wearing a lower rank uniform.
When Eva climbs on the table, Hewel is seen "helping" her, by touching her butt.
According to director Oliver Hirschbiegel in the B-roll commentary, the party happened in the private quarters of the old Chancellery but changed into the hall because it'd be hard for the filming crew to follow. He also said that by that time half of the building was destroyed and the dance was like a "dance of death". The take is not highly rehearsed, so the stuff with Hewel might all be random chances picked up by the camera.