The brick wall around the quad (which is actually known as "The Bull Ring") was constructed for the film and is merely a brick facade on wood. At the end of filming, students celebrated by tearing it down.
The "boys" who bought the adulterated mouthwash, ("Mr Burg, Mr Zarpas - Billy Tepper sold you a bottle of mouthwash with vodka in it... you have three seconds to hand it out here.") are two of this films' producers, Mark Burg and Chris Zarpas.
The scene where Billy eats a banana and throws the peel in the trash is improvised, including Dean Parker's response: 'Pick up that banana'. Before the cameras started rolling, Sean Astin asked a prop guy for a banana and then proceeded to eat it during the take, even adding a roll of the eyes when asked to pick up the peel. Aside from Louis Gosset Jr, actor reactions were pretty much genuine.
Jerry Orbach plays a similar character in the film, F/X playing a mobster in that film as well as this one. Mason Adams who also appeared in F/X also plays a similar character to the FBI agent he plays in that film in this one as well.
This film inspired somewhat by Red Dawn and Die Hard that had come out seven years earlier. In this film, these group of teens are fighting a group of terrorists in a confined space as opposed to an entire country or a skyscraper.
The second of back to back films that Andrew Divoff was featured as the villain. The other was Another 48 Hours, which had come out in the Summer of 1990 before principal photography on this film would take place.
R.Lee Ermey who plays the General in this film was in fact a real military soldier and appeared in a memorable performance in Stanley Kubrick's Full Metal Jacket. This would be the first of many films that Ermey would appear in as an actor during the 1990's in various roles (ie. Switchback, Leaving Las Vegas, The Frighteners, etc.)