The movie with the female villain with flames coming out of her arm is called Class of 1999.
Beginning narration states that throughout the 1990s, violence in American high schools had spiraled out of control, with areas in most major cities being taken over by youth gangs, resulting in some schools shutting down. Two major gangs vie for control.
In 1999, special areas known as "free fire zones" have discouraged police from entering out of fear. Seattle's Kennedy High School is in the middle of a free fire zone, thus the Department of Education Defense (D.E.D.), a pilot special government agency, has been notified. Working with MegaTech head Dr. Bob Forrest, an experiment begins where three former military robots have become android educators. Forrest introduces school coach Mr. Bryles, History teacher Mr. Hardin, and Chemistry teacher Ms. Connors to the Board of Education. Impressed with the new teachers, new principal Miles Langford has announced that former delinquents who are imprisoned will be released as part of the new experiment, which would allow new methods of discipline from the new teachers.
....
While they look for Christie and the teachers, they soon learn of the real deal with the teachers. Ms. Connors' arm becomes a flame thrower. Bryles' arm becomes a missile launcher.
Trailer