一方、その頃先生たちは…

The door was locked by the board chairman.
Meanwhile, the adults seem to be having a carefree lunch.
A teacher who brought a heart lunch box is being teased by the chancellor.

Meanwhile, the teachers were...

English:

The door was locked by the board chairman.
Meanwhile, the adults seem to be having a carefree lunch.
A teacher who brought a heart lunch box is being teased by the chancellor.