As a member of Verona’s Fire Department and Rescue Squad, Steve Giblin is accustomed to having to think fast in an emergency. But tomorrow night, he is going to have to think fast on stage. Giblin will be part of a performance by an improvisation class at the New Jersey School of Dramatic Arts in Bloomfield. He’s been taking classes there since January with Dan Ceppos, also of Verona. If you want to see what they’ve been learning at the school, which has other acting classes for adults and kids, the performances are at 8 and 9:30 p.m., and tickets are $10. The NJSDA is located at 593 Bloomfield Avenue in Bloomfield.