Contact tracing is hard – harder if you don’t know how high school works

The NYC DoE wrote this about contact tracing:

Tracing: In the event of a confirmed COVID-19 case in a school, NYC Test + Trace and NYC Health will investigate to determine close contacts within the school. All students and teachers in the classroom with the confirmed case are assumed close contacts and will be instructed to self-quarantine for 14 days since their last exposure to that case. In older grades where students may travel between classes, this applies to all classes that the confirmed case was in.

In older grades where students may travel between classes, this applies to all classes that the confirmed case was in.

Help me out here. “all classes that the confirmed case was in” – what do they mean? The rooms? Did they mean to say “all students who shared a class with the person with a confirmed case?” + “all teachers who taught that person?”

Why am I convinced that no one working on the NYCDoE plans has ever been to a high school?