Why: 'I am your disciple, teach me' is the real turning point, more than any later verse about the soul, because Arjuna stops trying to solve this alone.

In life: most of us hit a wall of a problem we can't think our way out of solo.

Teaching: asking for help isn't the failure point, it's usually where the actual movement starts. Notice when you're stuck for the third time on your own and say the equivalent of this line out loud, to someone.