Hermes put Argos to sleep with his flute.
The speaker is at first, afraid. They are struggling with their inner self about whether or not to jump. The speaker states that they struggle to the end. As the/she gets a look into the rippling water below, their fear grabs them even more. But soon, he/she states that a voice told them that if they were going to jump, to just jump. After another second of contemplation, the speaker finally overcomes their fear. Their transformation went from a person full of fear at the thought of jumping, to a person empty of that fear who cleared their mind and just did it.
Hope this helps!
Impetuous means done quickly and without a care
Im guessing the teacher is scary to the children