What was the announcement made by Corporal Turnbull in 'The Man Who Knew Too Much'?

What was the announcement made by Corporal Turnbull in ‘The Man Who Knew Too Much’? Why did he make the announcement?
or
What was Turnbull’s reaction to Private Quelch’s answer?

Corporal Turnbull announced that the platoon officer had asked him to nominate any one of the privates for permanent cook house duties and he had decided that Private Quelch was the right man for the job.
He made such an announcement in order to teach Private Quelch a lesson as he had interrupted him twice in the middle of his lecture.