Julian Moore is talking to Clive Owen just after he survives an explosion. She does not get the information she wants from him, so in retort she says this.
Julian: You know that ringing in your ears?? That EEEEEEEEE??? That's the cells in your ears dying, its kind of like their swan song. Once the ringing stops you'll never hear that frequency again...so enjoy it while it lasts.
This is one of my favorite movie quotes of all time. (If you do not know what a swan song is....wikipedia?!?!?!?)
