The teacher did not want to single out any specific student.
single out
idiomTo select (someone or something) from a group and highlight them or treat them differently.
Origin
first recorded 17th c.From single (“to take alone, or one by one”, intransitive archaic verb) + out. First attested in 1629.
During the meeting, the manager decided to single out Sarah for her excellent work on the project.
Although the entire team contributed to the success, the director chose to single out the lead architect for special recognition during the ceremony.