Gib is one of the funniest sidekick characters ever in an action film.
Gib: Same thing happened to me with wife number two, remember? I have no idea nothing's going on, right? I come home one day and the house is empty, and I mean completely empty. She even took the ice cube trays out of the freezer. What kind of a sick bitch takes the ice cube trays out of the freezer?
Where do we start with the shootout and first confrontation between Aziz and Harry?
Aziz fires at Gib, whose only cover is a light post. He turns to hide behind it, and the bullets can clearly be seen striking both the post and the area around it, but somehow managed to miss Gib entirely despite the fact that he clearly sticks out from both the front and back.
Gib's reaction: He feels up and down his body to make sure he hasn't been hit anywhere, ending with his crotch, before muttering "Oh thank God..."
The poor old man caught in the middle of the bathroom shootout
Their vehicles for the subsequent chase: Aziz's motorcycle vs. Harry's commandeered police horse.
Harry:(gives directions to Gib to get backup to catch Aziz) All right, and make it happen quick, because my horse is getting tired. Gib:(beat) Your horse?
Harry:(after the horse refuses to jump from one building to the next and Aziz escapes) Now what the hell were you thinking? I mean, I had the guy, and you let him get away. (horse looks away; Harry pulls it back) Look at me when I'm talking to you. What kind of a cop are you?
Harry's conversation with the torturer.
Samir: Is there anything you'd like to tell me before we start?
Helen's first experience with a MAC-10. The recoil makes her lose control and drop the gun down the stairs...and it continues to fire, miraculously taking out every Mook in the room.
Topped by the look of impressed astonishment and stunned disbelief on Harry's face after he surveys Helen's handiwork.
As Helen was readying to shoot, Harry was busy struggling with another mook; when Helen's dropped gun starts to spray fire everywhere, Harry and the mook stop their fight and run for cover. On top of that, several mooks come around the corner, see the falling gun, and immediately try to run back (and get shot doing so).
"Oh yeah, she's got her head in the guy's lap all right. Yahoo."
(mook nervously lowers camera and Aziz stops, throwing his hands up in a "What gives?" motion)
Mook: Battery, Aziz!
(There is dead silence as Aziz threateningly approaches him. And...)
Aziz: Get another one, you moron!
Mook: I think I have one—
Aziz: Shh! (raises silencing hand and shoos him away in annoyance)
Mook: ...in the truck. *runs*
When Harry and Gib are listening to Simon bullshitting over the wiretap:
Simon: It's the training. It shapes you into a lethal instrument. You react without thinking. Gib: I'm starting to like this guy. (notices Harry's Death Glare) Oh, we still gotta kill 'im. That's a given.
The final line in the movie, after Gib is annoyed that Harry and Helen ignored him over the earpiece while on mission:
Gib: Y'know what? I'm sick of being in the van. You're going in the van next time. I've been in the van for fifteen years, Harry.
Gib finally having enough of Simon annoying him and Harry, and starts casually shooting at his feet.
Gib: (bored tone) Get lost, dipshit.
Aziz fist pumping in celebration after apparently blowing up Harry with a rocket launcher.
During the striptease scene, Harry has the taped dialogue asked Helen to dance. After she starts an out-of-place dance, the next message is "No no no, dance sexy." Harry correctly predicted she would dance like a goofball and pre-recorded dialogue to compensate for it.
When Gib tries to hide a transcript detailing Helen meeting up with Simon, Harry yells "GIMME DAH GAHDDAMN PAGE!" and smashes a window with his fist. It's hilarious in its own right, but it's even funnier if you know the filming context like the striptease accident above: Arnold was supposed to hit a window rigged with safety glass, but broke a real window instead. Tom Arnold played it with the speechless reaction that the scene called for, but one would imagine part of it was also seeing his co-star breaking a car window for real with an Offhand Backhand.