I’ve seen this episode a bunch of times, but only having seen Kill Bill vol. I recently did I realize that the musical piece that is played when the car backfires at the end of Act 1, and Joey dives onto Ross is the piece from the TV show Ironside, which was used in Kill Bill whenever Beatrix locked eyes with her enemies.

---Great Exchange:
Chandler: It was a car back-fire.
Ross: “Yeah, but... but he didn't know that.”
Joey: “Yeah, I didn't know that!”
Ross: “And it could've just as easily had been a bullet.”
Gary: “Yeah, Joey, you ever think about joining the force? We could use a guy like you.”
Chandler: .”..who jumps at loud noises.”
Ross: “Wow, I could have died tonight.”
Chandler: “Yeah, if the car that back-fired had run over you.”

Great exchange (from memory; the gang are discussing how they would act in a war zone)
Ross (punches Joey playfully): Joey would be the guy jumping into the foxhole to protect his comrades!
(Joey looks embarrassed)
Chandler: Sure. If it was lined...with...SANDWICHES!!

TRIVIA: Arguing over who gets to ride in the cop car's front seat, Ross says to Joey and Chandler, “I'm more cop than you two.” This is another reference to David Schwimmer's stint on NYPD Blue.