Terror Squad (1988)

Four Arab terrorists, probably Libyans, sneak into the US through the Canadian border. They badly botch an attempt to blow up a nuclear power plant in Indiana. The four that survive are badly pursued by the police, who mostly crash their cars. The terrorists shoot up a town's main street and run down an old man with their car. The pursuing police chief then runs over the old man (a bad dummy).

Meanwhile, a bunch of actors apparently in their twenties are portraying high school students. One of them plays guitar with the janitor, except that on the soundtrack is bad synthesizer music, the same kind of bad synthesizer music that is on the soundtrack. Later, a bunch of the students are in detention. The guitarist plays some more synthesizer music in detention, even though he doesn't have an amp. A jock makes farting sounds with his armpit, except that it sounds more like a synthesizer playing fart sounds.

The now two surviving terrorists, apparently having evaded the police, burst into the detention room. Thus the stereotypical Arabs meet the stereotypical high school students. The police and SWAT surround the school, and miss dozens of opportunities to get into the school and/or shoot the terrorists. The students and their teacher frequently do things to make the terrorists nervous and angry (and one of them is quick to anger anyway), which only results in getting themselves injured or killed.

As others have noted, when the terrorists leave the school in a bus, they are very clearly in a full-length bus. At some point while the police are following them to the airport, it clearly turns into a short half-length bus. I'm at a loss to explain how the filmmakers thought they could get away with that, especially since there are lengthy shots of the bus both when it is long and when it is short.