The hand dryer

Original fiction extract.

The little boy recoiled when the hand dryer started. A moment earlier he had been reaching towards its smooth silver opening as though expecting a towel. His father waited beside him without laughing. They watched another visitor use it, and the boy came closer again, keeping one hand in his father’s. This time he put only his fingertips under the warm air. Afterwards he shook both hands vigorously, although they were already dry, and inspected the machine from a safer distance.

Identify a word or phrase from the extract which suggests the same idea as the words in bold:

The little boy moved back suddenly in alarm when the dryer started.