If you pause on one of the flashes you can see the director and extras on set--right before the scene with the taxi and the two drivers arguing. Also you can see clips from E!. They are behind the scenes on the set of Angel.
Angel looks at the photo of the convenience store attack and says it took place at 11:24. The photo is timestamped 10:52.
Watch at the end when Fred leaves Wesley's apartment: you can just make out actress Amy Acker stumbling into either the cameraman or some equipment.
Fred: It wasn't something in you Wesley. It was something that was done to you.
Wesley: I don't know what kind of man I am anymore.
Fred: Well, I do. You're a good man.
Wes: (To Fred) What do you tell a woman with two black eyes? Nothing you haven't already told her twice.
Angel: Is Billy here?
Dylan: You a friend of his or something?
Angel: Actually I'm here to kill him.
Dylan: Oh come on in.
Gunn: (Playing a video game) Dead! So dead! So very, very dead, just how dead are you, huh?
Angel: I'm tired of being the dead one.
Cordelia: (Looking at a picture of Billy) You're sure this is him? This is the guy?
Angel: You pull someone from a hell dimension; you tend to remember their face.
Cordedia: (To Lilah) Angel feels responsible for this guy because he brought him back from hell. I feel responsible because he did it to save me. You, who are actually responsible for the entire thing, feel nothing at all, because you are a vicious bitch.
Lilah: So you know me.
Cordelia: Please, I was you. With better shoes.
Lilah: These are Boracci.
Cordelia: Fall collection?
Lilah: Next spring.
Cordelia: He's widened the heel.
Lilah: And rounded the toe.
Cordelia: That won't work with pink.
Lilah: The pink is out this spring.
Lilah: Cordelia Chase, right? Come to gloat?
Cordedia: I can do that anywhere. Are you gonna invite me in? Oh, wait. I'm not a vampire.
Cordelia: You know that guy that you hired to hack into my visions? What he did to me? What it felt like? I was cut, my face disfigured, and burning with pain every second not knowing if it was going to end or just get worse till I died.
Lilah: So you think I owe you...
Cordelia: It's not the pain. It's the helplessness. The certainty that there is nothing you can do to stop it, that your life can be thrown away in an instant by someone else. He doesn't care. He'll beat you down until you stay down because he doesn't even think of you as alive. No woman should ever have to go through that, and no woman strong enough to wear the mantel of "vicious bitch" would ever put up with it. Where is Billy going?
Angel: You know, Cordelia, handling a lethal weapon is a little different than shaking a pom-pom.
Cordy: Ready! Okay! (goes through combination sword kata and cheerleader routine)
Angel: Easy. (Cordelia pins him to wall, sword at his throat) Go team!
Angel: That thing that Billy brought out in others? The hatred and anger... that's something I lost a long time ago.
Cordelia: Even when you were evil?
Angel: I never hated my victims, I never killed out of anger, it was always about the - pain and the pleasure.
Gunn: You mean, that, that fingerprinty looking handprint downstairs is Billy's blood? So, you're saying that Wes turned into psycho killer because of that bloody handprint that I picked up and looked at?
Fred: When you put it that way, it kinda worries me.
Wes: Speaking of saliva, where is Cordelia?
Dylan: There was a chick here. She was cute, brunette. Well, she said that a melodramatic guy named Angel would eventually show up.
Angel: Cordelia... thinks I'm melodramatic?
Dylan: Well, you did say that you were going to kill my cousin.
The original version of Gavin attacking Lilah was originally more graphically violent (you saw the beating), it was cut and shortened due to censors.
When Billy is visiting his cousin -- "Clint Eastwood" by The Gorillaz
When Angel goes to see Billy's cousin -- "Slow" by Elwood
In the script Angel's penchant for quick exits is exemplified in this stage direction from the shooting script: WHOOSH - Angel's off into the night. WESLEY'S POV. The dark figure of Angel just disappearing over a roof (or around a corner. Point is, he ain't Superman, but we get that the cat can cook when he wants to).
Joss wrote two scenes for this episode: Angel at Lilah's apartment and Cordelia at Lilah's apartment.
On the back of the UK video release, David Greenwalt is accidentally credited as writing this episode.
Wesley: (Chases Fred through the Hyperion with an axe)
This scene was largely inspired by Stanley Kubrick's 1980 horror classic The Shining in which Jack Nicholson's character goes mad, carries an axe and begins hunting his wife (Shelley Duvall) throughout a large, creepy and empty hotel. The film itself was inspired by Stephen King's novel of the same name.
Cordelia: You can't barge into a police precinct and go all Terminator.
In James Cameron's original Terminator movie, Arnold Schwarzenegger plays a seemingly unstoppable android from the future on a quest to kill one woman and anyone who stands in his way. At one point he drives into a police station and shoots up the place killing most of the police inside.