Upon logging in, players level 30 or higher will see a cinematic of the attack on Lion’s Arch. Lower level players will watch this upon entering Lion’s Arch for the first time. …
Note: All characters that were stationed in Lion’s Arch before the attack will be relocated to an adjoining map.
This is not true. If you were stationed in Lion’s Arch before the attack, the cinematic will play once you log in. Your character will stand in the exact spot where you logged off, and the monsters that now spawn in Lion’s Arch will kill you.
The sound effects you hear are not part of the cinematic. The screams of the injured and dying are coming from characters who also logged off in Lion’s Arch.